Textile products having selectively applied sealant or coating

ABSTRACT

An implantable tubular textile graft includes a water-insoluble elastomeric sealant disposed at the textile tubular wall such that the graft is impermeable to water at 120 mm Hg pressure. The inner surface of the textile tubular wall configured to promote growth of biological tissue and/or promote growth of pseudointima.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Pat. Application No.17/308,383, filed May 5, 2021, which is a Continuation of U.S. Pat.Application No. 16/407,041, filed May 8, 2019, now U.S. Pat. No.11,027,046, issued Jun. 8, 2021, which is a Continuation-In-Part of U.S.Pat. Application No. 16/273,320, filed Feb. 12, 2019, now U.S. Pat. No.10,926,003, issued Feb. 23, 2021, which is a Continuation ofInternational Application No. PCT/GB2018/053161, filed Oct. 31, 2018,which designated the United States of America, and which embodimentsclaim the benefit of Great Britain Application No. GB 1717885.6, filedOct. 31, 2017, the contents of all of which are incorporated byreference herein.

FIELD OF THE INVENTION

This invention relates to textile products, such as a vascular orendovascular prostheses having a selectively applied sealing layer orcoating and particularly but not exclusively, a method of manufacturingthe textile products, such as prostheses, a kit of parts formanufacturing the textile products, such as prostheses, a vascularsystem including the prosthesis, a method of implanting the prosthesisand a method of implanting the vascular system.

BACKGROUND TO THE INVENTION

Vascular prostheses, or grafts, are used extensively in surgicalprocedures, such as in treating abdominal and thoracic vascular disease.Vascular grafts are typically required to be sealed prior toimplantation, in order to prevent blood from leaking from the vasculargraft after implant. Known techniques for sealing vascular graftsinclude the use of biodegradable (or bioresorbable or bioabsorbable)animal-derived materials such as bovine gelatine, bovine albumin orbovine collagen to seal the graft. Other techniques for sealing vasculargrafts use synthetic materials, some of which are not able to biodegradewhen implanted in a human or animal body.

It is desirable for the sealed graft, once implanted in a human or ananimal body, to allow the ingrowth of tissue on the inner surface of thevascular graft and to ensure that the ingrowing tissue adheres to theinner surface of the vascular graft. However, conventional techniquesfor sealing vascular grafts often suffer from the ingress of the sealantinto the inner surface of the vascular graft. The presence of sealingmaterial has an adverse effect on the growth of tissue on the innersurface of the graft. Furthermore, the presence of sealing material onthe inner surface of the graft also contributes to poor adhesion betweenthe ingrowing tissue and the vascular graft, which can lead to reducedvascular performance of the vascular graft. It is therefore desirable toprovide a vascular graft which does not hinder the ingrowth of tissueand which allows the ingrowing tissue layer to adhere to the innersurface.

In an attempt to better enable growth and adhesion of tissue on theinner surface of the graft, biodegradable animal-derived materials suchas those noted above can be used to seal the graft. When such a graft isimplanted, it is desirable for the sealant material to degrade once theingrowing tissue layer is sufficiently mature. However, conventionalmethods of sealing vascular grafts do not exhibit consistent andpredictable degradation times. This has considerable implications on theperformance of some vascular grafts. For example, if the sealantmaterial degrades before the ingrowing tissue layer has developed into apseudointima (an example of a tissue layer on the inner surface of avascular graft), blood will leak from the vascular graft. If the sealantmaterial degrades too slowly, the ingrowing tissue will suffer from pooradhesion to the inner surface of the graft (because the inner surface ofthe graft is still coated in sealing material), and is likely todelaminate from the vascular graft. Haemorrhagic dissection could thenoccur in the pseudointima. There is therefore a need to provide a methodof sealing vascular grafts that enables predictable growth and adhesionof tissue to the inner surface of the vascular graft.

A further issue with existing vascular grafts is that someanimal-derived sealants of the type typically used are thought toincrease the risk of bovine spongiform encephalopathy (BSE)transmission. This risk is usually mitigated by extensive supply chainregulation requirements, which are onerous and burdensome. It isdesirable to provide a vascular graft which has less burdensomeregulatory requirements, such that new materials and designs can bebrought to use in a shorter time and in a more cost-effective way.

Furthermore, animal-derived sealants are incompatible with an array ofprocessing techniques, which limits the options available to vasculargraft designers. Vascular grafts sealed using animal-derived sealantsare also typically required to be transported, or packaged, with controlover the temperature and humidity to obviate deterioration of thesealant material. Therefore, it would also be desirable to provide avascular graft which has less stringent transport and packagingrequirements.

Furthermore, elastomeric coatings may change the flexibility of thefabric and, when fashioned into medical products such as vascular graftsand the like, may have a deleterious effect on the handlingcharacteristic which are very important to surgeons. Thus, it would bedesirable to provide a vascular graft which has sufficient sealing dueto an elastomeric coating on the external surface and which issubstantially free of the same coating material on the opposing side,e.g., luminal side, and also has flexibility and handlingcharacteristics acceptable to surgeons.

SUMMARY OF THE INVENTION

The masking agent may be a water-soluble polymer layer, a water-solublepolymer, a water-soluble material, a water-soluble coating and/or awater-soluble layer.

The sealant may be a water-insoluble material, a water-insolublesealant, a water-insoluble coating, and/or a water-insoluble layer.

For purposes of this invention, the water-soluble layer and thewater-insoluble layer are applied to textile fabrics, medical devicefabrics, implantable medical device textiles and various configurationsof medical and non-medical textiles.

It is an object of the present invention to provide a vascularprosthesis and/or a method of manufacturing a vascular prosthesis, theinner surface of which better allows the ingrowth of biological tissue.One aspect of the present invention is to provide an implantabletextile, such as a vascular prosthesis, and/or a method of manufacturingan implantable textile, such as a vascular prosthesis, the inner surfaceof which better allows the ingrowth of biological tissue. It is afurther aspect of the present invention to provide an implantabletextile, such as a vascular prosthesis, and/or a method of manufacturingan implantable textile, such as a vascular prosthesis, the inner surfaceof which is substantially devoid of sealing material. Another aspect ofthe present invention is to provide a vascular prosthesis and/or amethod of manufacturing a vascular prosthesis, which better facilitatesingrowing tissue to adhere to the inner surface of the vascularprosthesis. It is a further aspect of the present invention to provide avascular prosthesis and/or a method of manufacturing a vascularprosthesis, which better allows for predictable growth and adhesion oftissue to the inner surface of the vascular prosthesis. It is still afurther aspect of the invention to provide a vascular prosthesis whichstrikes a balance between too much and too little masking agent. Toolittle masking agent will allow the sealant to migrate through the graftwall. Too much masking agent on the outside interferes with sealantadhesion and thus affects the ability to reach the permeability that isrequire in a vascular prosthesis. There must be sufficient masking agentto prevent sealant penetration balanced with the amount of masking agentthat ends up on the outer graft surface. It is also an aspect of theinvention to achieve a balance between the amount of sealant coverageand sealant adhesion required to attain adequate sealing and too muchsealant such that it destroys the flexibility and handlingcharacteristics of the prosthesis.

It is also a further aspect of the present invention to provide a kit ofparts for manufacturing a vascular prosthesis. It is a further aspect ofthe present invention to provide a vascular system which allows, forexample, synthetic assistive heart components to be connected to bloodvessels and the heart.

It is a further aspect of the present invention to mitigate or at leastobviate at least some of the issues in the prior art. Further aspectsand embodiments of the present invention will be apparent from a readingof the present document.

According to a first aspect of the invention there is provided a methodof manufacturing a vascular prosthesis, the method comprising the stepsof:

-   (i) providing a conduit comprising a wall, the wall of the conduit    comprising an inner surface and an outer surface, at least a section    of the conduit being porous;-   (ii) adding a masking agent to at least a part of the porous section    of the conduit; and-   (iii) adding a sealant to at least a part of the porous section of    the conduit, the sealant being configured to mitigate movement of    fluid through the wall of the conduit;

wherein the masking agent is configured to mitigate presence of thesealant on the inner surface of the conduit.

The vascular or endovascular prosthesis of the present invention is notlimited to a prosthesis comprising a conduit or tubular portion. Thevascular or endovascular prosthesis of the present invention may be ormay comprise a non-conduit or non-tubular shaped structure or portion.Thus, the wall of the vascular or endovascular prosthesis beingsubjected to the masking agent and the sealant is not limited to aconduit wall. Thus, a substrate may be a non-conduit shaped structure orportion. Further, medical textile products are within the scope of thepresent invention.

The sealant may form a sealing layer on at least a part of the outersurface of the wall of the conduit.

The sealant may form a sealing layer on substantially all of the outersurface of the wall of the conduit.

The masking agent may form a masking agent layer on at least a part ofthe inner surface of the wall of the conduit.

The masking agent may form a masking agent layer on substantially all ofthe inner surface of the wall of the conduit.

Substantially all of the conduit may be porous.

The method may comprise one or more masking agent removal steps, the, oreach, masking agent removal step comprising the step of removing atleast a part of the masking agent from the conduit.

The method may comprise the step of removing at least a part of themasking agent from at least a part of the outer surface of the wall ofthe conduit prior to the step of adding the sealant to the poroussection of the conduit.

The method may comprise the step of removing at least a part of themasking agent from the inner surface of the wall of the conduitsubsequent to the step of adding the sealant to at least a part of theporous section of the conduit.

The method may comprise the step of removing substantially all of themasking agent from the conduit subsequent to the step of adding thesealant to at least a part of the porous section of the conduit.

At least one of the masking agent removal steps may be carried out at atemperature of between approximately 15° C. and approximately 140° C.

At least one of the masking agent removal steps may comprise the step ofremoving at least a part of the masking agent by applying a solventthereto.

The solvent may comprise water.

The conduit may be at least one of: agitated, rotated, spun, and shaken,or the like, during at least one of the masking agent removal steps.

At least one of the masking agent removal steps may be carried out byetching, plasma etching, ablating and/or abrading the masking agent.

The inner surface of the wall of the conduit may be configured topromote the growth of biological tissue thereon.

The masking agent may comprise a polymer.

The masking agent may comprise a water-soluble polymer.

The masking agent may comprise at least one of: polyvinylpyrrolidone,glycerol, methyl cellulose, poly(ethylene glycol) and poly(ethyleneglycol) hydrogel. The masking agent may comprise at least one of:polyvinylpyrrolidone (PVP), glycerol, methyl cellulose, poly(ethyleneglycol) (PEG), polyethylene oxide (PEO), and poly(ethylene glycol)hydrogel. The masking agent may also include other biologicalhydrophilic polymers as described herein.

The masking agent may be biocompatible.

The masking agent may form a biocompatible masking agent layer whenadded to the conduit.

The masking agent may be added to at least a part of the porous sectionof the conduit from a masking agent solution. As used herein porousrefers to being permeable to the passage of liquids such as blood undernormal physiological conditions in a human patient.

The masking agent solution may be a polymer solution.

The step of adding the masking agent to at least a part of the poroussection of the conduit may be performed by spraying the masking agentsolution onto at least a part of the porous section of the conduit.

The masking agent solution may be added to the conduit by spraying themasking agent onto at least a part of the inner surface of the wall ofthe conduit.

The step of adding the masking agent to at least a part of the poroussection of the conduit may be performed by immersing at least a part ofthe porous section of the conduit in the masking agent solution.

Substantially all of the conduit may be immersed in the masking agentsolution.

The masking agent solution may comprise between approximately 5%weight/volume (w/v) of polymer in solution and approximately 30% w/v ofpolymer in solution.

The method may be carried out such that the step of adding the sealantto at least a part of the porous section of the conduit does not resultin the removal of the masking agent from the porous section of theconduit.

The masking agent may be configured to biodegrade when the vascularprosthesis is implanted inside the human or animal body.

The conduit may be a woven fibrous polymer conduit.

The sealant may comprise a polymer.

The sealant may be a water-insoluble polymer.

The sealant may form a sealing layer when added to the conduit, thesealing layer being a polymer layer.

The sealant may comprise at least one of: silicone, room temperaturevulcanising silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, and polycarbonate.

The sealant may be added to the conduit from a sealant solution.

The sealant solution may be a polymer solution.

The sealant solution may comprise an organic solvent.

The sealant solution may comprise at least one of heptane and xylene.

The sealant may be added to at least a part of the porous section of theconduit by brushing and/or spraying the sealant thereon.

The sealant may be configured to mitigate movement of blood through thewall of the conduit.

The weight ratio of the sealant to the masking agent may be from about0.1:1 to about 100:1. The weight ratio of the sealant to the maskingagent may be from about 0.1:1 to about 71:1. The weight ratio of thesealant to the masking agent may be from about 0.1:1 to about 31:1.

The method may comprise the further step of sterilising the vascularprosthesis. The method may comprise the further step of sterilising thevascular prosthesis and/or medical device containing the textilesubstrate of the present invention.

The vascular prosthesis may be sterilised by way of at least one of: agamma sterilisation process, an electron beam sterilisation process, andan ethylene oxide sterilisation process.

The conduit may be moveable between a contracted state and an extendedstate. The conduit may comprise a plurality of crimps. The conduit maycomprise a plurality of crimps to provide, for example, flexibility forextending and contracting the conduit or prosthesis.

The step of adding the masking agent to at least a part of the poroussection of the conduit may be carried out, at least in part, while theconduit is in the contracted state, in the extended state, and/or whenmoved between the contracted state and the extended state.

The step of adding the sealant to at least a part of the porous sectionof the conduit may be carried out, at least in part, while the conduitis in the contracted state, in the extended state, and/or when movedbetween the contracted state and the extended state.

The method may comprise one or more steps of weighing the conduit and/ormeasuring the length of the conduit, to determine, at least in part, theamount of masking agent, and/or or the amount of sealant, to add to atleast a part of the porous section of the conduit.

The step of adding the masking agent to at least a part of the poroussection of the conduit may comprise the step of providing gas to theconduit.

The gas may be directed towards the outer surface of the wall of theconduit.

The gas may be air.

The method may comprise the step of adding a support member to theconduit.

The support member may be added to the outer surface of the wall of theconduit.

The support member may be wrapped around the outer surface of the wallof the conduit.

The conduit may comprise a plurality of crimps, and the support membermay be arranged to nest between the plurality of crimps.

The step of adding the support member to the conduit may be carried outprior to the step of adding the sealant to the conduit.

The step of adding the sealant to the conduit may be used, at least inpart, to attach the support member to the conduit.

The support member may be a flexible, polymer member.

The method may comprise one or more steps of selectively adding sealantto one or more sections of the conduit, such that the conduit comprisesat least two sections comprising substantially different amounts ofsealant thereon.

The vascular prosthesis may be reversibly sealable. The masking agentmay be selectively removable from the conduit. The masking agent may beadded to, and subsequently removed from, the conduit. The sealant may beselectively removable from the conduit. The sealant may be added to, andsubsequently removed from, the conduit. The masking agent and thesealant may be selectively removable from the conduit. The masking agentand the sealant may be added to, and subsequently removed from, theconduit.

The method may comprise one or more steps of adding the sealant to theconduit. The conduit may be configured to have variable flexibilitythroughout its length. The method may comprise the step of decreasingthe flexibility of one or more sections of the conduit by adding sealantthereto. The method may comprise the step of selectively adding sealantto one or more sections of the conduit, such that the conduit comprisesat least two sections comprising substantially different amounts ofsealant thereon. The method may comprise one or more steps ofselectively adding sealant to one or more sections of the conduit. Theone or more steps of selectively adding sealant to one or more sectionsof the conduit may include adding sealant onto sealant that is presenton the conduit. In this arrangement, different sections of the conduitmay be configured to have different degrees of flexibility.

The vascular prosthesis may be configurable to be implantable inside thehuman or animal body. The vascular prosthesis may be configurable to beimplantable or deliverable inside the human or animal body. The vascularprosthesis may be configured to be implantable inside the human oranimal body. The vascular prosthesis may be configured to be implantableor deliverable inside the human or animal body.

The vascular prosthesis may be biocompatible. The term biocompatibleused herein is in reference to materials which are compatible withimplantation in the human or animal body, that is materials which can beimplanted in the human or animal body without being harmful or toxic tosurrounding tissue. The vascular prosthesis may be made frombiocompatible materials. The vascular prosthesis may be made fromsubstantially entirely biocompatible materials.

The vascular prosthesis may be a vascular graft. The vascular prosthesismay be configured to be flexible. The vascular prosthesis may beflexible.

The vascular prosthesis may have an inlet and an outlet. The vascularprosthesis may be configurable to allow fluid to flow from the inlet ofthe vascular prosthesis to the outlet of the vascular prosthesis. Thevascular prosthesis may be configured to obviate fluid leakingtherefrom. The vascular prosthesis may be configured to allow fluid toflow from the inlet of the vascular prosthesis to the outlet of thevascular prosthesis, and to prevent fluid from leaking from the vascularprosthesis. The step of adding the sealing layer to the porous sectionmay configure the vascular prosthesis to obviate fluid leakingtherefrom. The fluid may be a liquid. The fluid may be blood. It will beunderstood that the vascular prosthesis may be configured to obviateand/or prevent fluid leaking therefrom insofar as it is configured toobviate and/or prevent fluid from passing through the wall of theconduit of the vascular prosthesis.

The step of adding the sealant to at least a part of the porous sectionof the conduit may convert the conduit to a vascular prosthesis.

The vascular prosthesis may be made substantially entirely frompolymeric materials.

The vascular prosthesis may be configured to obviate the leaking ofblood therefrom at a blood pressure of up to approximately 300 mmHg (40kPa), optionally up to approximately 200 mmHg (26.7 kPa).

The conduit may be made from a polymer material. The conduit may be apolymer conduit. The conduit may be made from one or more polymers. Theconduit may be a woven conduit. The conduit may be a knitted conduit.The conduit may be made from woven fibres. The conduit may be a woven,polymer, fibrous conduit. The conduit may comprise polyester. Theconduit may comprise polytetrafluoroethylene (PTFE). The conduit maycomprise polyethylene terephthalate (PET). The conduit may comprisepolyurethane (PU).

The method may comprise the step of applying heat to the conduit. Themethod may comprise the step of altering the shape of the conduit byapplying heat to the conduit.

The conduit may be substantially cylindrically shaped. The conduit maybe substantially tube shaped. The conduit may have a diameter of up toapproximately 44 mm, optionally between approximately 8 mm andapproximately 32 mm. The conduit may have a substantially uniform crosssection throughout.

The conduit may comprise one or more crimps. The method may comprise thestep of adding one or more crimps to the conduit. The method maycomprise the step of mounting the conduit on a frame member. The methodmay comprise the step of affixing the conduit to a frame member. Theframe member may be configurable to allow the conduit to move from thecontracted state to the extended state. The frame member may beconfigurable to allow the conduit to move from the extended state to thecontracted state. In the contracted state, the conduit may comprisebetween approximately 7 crimps per cm of length of the conduit andapproximately 10 crimps per cm of length of the conduit. In the extendedstate, the conduit may comprise between approximately 4 crimps per cm oflength of the conduit and approximately 6 crimps per cm of length of theconduit.

The conduit may comprise a twill-weave section. The conduit may be atwill-weave conduit. The conduit may be a 1/1 twill-weave. The conduitmay comprise a plain-weave section. The conduit may be a plain-weaveconduit. The weft yarn pick-rate of the conduit may be betweenapproximately 25 ppcm and approximately 50 ppcm, optionally betweenapproximately 36 ppcm and approximately 45 ppcm. Useful yarns mayinclude multifilament yarns.

The conduit or medical textile is not limited to a woven textile. Othertextile constructions, such as knitted textiles, braided textiles,fabric webs, fabric felts, filament spun textiles, and the like, can beused. Such textile or fabric constructions may be used with the methods,coatings, and/or masking agents of the present invention in both medicalapplications (including vascular and non-vascular applications) andnon-medical applications.

In general, useful yarn materials include, but are not limited to,polyesters, polypropylenes, polyethylenes, polyurethanes,polytetrafluoroethylenes, and combinations thereof. The yarns may be ofthe monofilament, multifilament, or spun type. Multifilament yarns maycontain from about 8 filaments to about 96 fiber filaments, desirablyfrom about 20 filaments to about 40 filaments, more desirably from about25 filaments to about 30 filaments. The yarns may have a linear densityfrom about 18 denier (about 20 decitex) to about 140 denier (about 154decitex), more desirably from about 30 denier (about 33 decitex) toabout 60 denier (about 67 decitex), more desirably from about 40 denier(about 44 decitex) to about 45 denier (50 decitex). The yarns may beflat, twisted, and/or textured, and may have high, low or moderateshrinkage and/or bulk and crimp properties. Twisted yarns includeS-twisted yarns and Z-twisted yarns. The number of twists per inch mayvary from about 2 twists per inch (about 0.8 twists per cm) to about 15twists per inch (about 6 twists per cm), more desirably from about 5twists per inch (about 2 twists per cm) to about 12 twists per inch(about 5 twists per cm). Desirably, the yarns are single ply yarns ormulti-ply yarns. Multi-ply yarns may contain from about 2 yarns per plyor bundle to about 4 yarns per ply or bundle.

The textile graft of the present invention may be woven from yarns usingany known weave pattern, including simple plain weaves, basket weaves,twill weaves, velour weaves and the like. Weave patterns include warpyarns running along the longitudinal length of the woven product andweft also known as fill yarns running around the width or circumferenceof the woven product. The warp and the fill yarns are at approximately90 degrees to one another with fabric flowing from the machine in thewarp direction. The weave pattern may have from about 80 to about 325warp yarns per inch (about 30 to about 128 warp yarns per cm) and about80 to about 200 fill or weft yarns per inch (about 30 to about 80 fillyarns per cm). The wall thickness may be any conventional usefulthickness, for example about 0.04 mm to about 1 mm.

Knitting involves the interlooping or stitching of yarn into verticalcolumns (wales) and horizontal rows (courses) of loops to form theknitted fabric structure. In warp knitting, the loops are formed alongthe textile length, i.e., in the wale or warp direction of the textile.Non-limiting stitch counts may include about 20 to about 60 wales perinch per layer (about 8 to about 25 wales per cm per layer) and 30 to 80courses per inch per layer (about 12 to about 32 courses per cm perlayer). Non-limiting overall number of stitches may vary from about 600to about 5,000 stitches per square inch (about 100 to about 900 stitchesper square centimeter). Useful knitting patterns include, but are notlimited to, locknit knits (also referred to as tricot or jersey knits),reverse locknit knits, sharkskin knits, queenscord knits, atlas knits,velour knits, and the like. The wall thickness may be any conventionaluseful thickness, for example about 0.1 mm to about 1.5 mm.

The conduit may comprise one or more inlets. The conduit may compriseone or more outlets. The conduit may be a Y-shaped conduit. The conduitmay be a T-shaped conduit. The conduit may be one or more of acylindrical, tubular, Y-shaped, T-shaped, and multi-channel conduit. Theconduit may have a bulbous shape or a portion having a bulbous shape.Such a bulbous shape may have, but is not limited to, a Valsalva aorticroot profile. The present invention, however, is not limited to theconduit-shaped textiles. Other shaped textiles, such as planar or shapedsheets or tapes, may be used with the present invention.

The conduit may be a porous conduit. The conduit may be a porousconduit, for example having a water permeability of greater than 0.16ml/min/cm² at 120 mm Hg pressure.

The inner surface of the wall of the conduit may be configured topromote biological tissue growth thereon. The inner surface of the wallof the conduit may be configured to allow biological tissue to growthereon. The inner surface of the wall of the conduit may be configuredto promote the growth of biological tissue thereon, at least in part bybeing substantially devoid of the sealant. The inner surface of the wallof the conduit may be configured to promote the growth of pseudointima.The inner surface of the wall of the conduit may be configured to allowthe growth of pseudointima to occur thereon. The inner surface of thewall of the conduit may be configured to promote the adhesion ofbiological tissue thereto. The inner surface of the wall of the conduitmay be configured to allow biological tissue to adhere thereto. Theinner surface of the wall of the conduit may be configured to promotethe adhesion of platelets thereto.

The inner surface of the wall of the conduit may be fibrous. The innersurface of the wall of the conduit may comprise woven fibres. The innersurface of the wall of the conduit may comprise a braided section. Theinner surface of the wall of the conduit may be a substantially braidedsurface.

The masking agent may form a sacrificial layer. The masking agent mayform a masking layer. The masking agent may form a sacrificial maskinglayer on at least a part of the conduit. The masking agent may bereversibly applicable to the conduit.

The masking layer may be an oleophobic layer.

The masking agent may be added to at least a part of the conduit. Themasking agent may be added to substantially all of the conduit. Themasking agent may be added to substantially all of the porous section ofthe conduit. The masking agent may be added to the inner surface of thewall of the conduit.

The method may comprise the further step of removing at least part ofthe masking agent from the conduit. The method may comprise one or moremasking agent removal steps. The masking agent may be removed from theconduit by applying a masking agent remover to the masking agent.

The method may comprise a first masking agent removal step carried outprior to the step of adding the sealant to at least a part of the poroussection. The method may comprise a second masking agent removal stepcarried out subsequent to the step of adding the sealant to at least apart of the porous section of the conduit. The method may comprise afirst masking agent removal step carried out prior to the step of addingthe sealant to at least a part of the porous section, and a secondmasking agent removal step carried out subsequent to the step of addingthe sealant to at least a part of the porous section of the conduit.

The method may comprise the step of removing at least a part of themasking agent from the outer surface of the wall of the conduit. Themethod may comprise the step of removing at least part of the maskingagent from the outer surface of the wall of the conduit, prior to theaddition of the sealant. The method may comprise the step of removing atleast a part of the masking agent from the outer surface of the wall ofthe conduit, such that at least a part of the outer surface of the wallof the conduit is devoid of the masking agent. In this arrangement, thesealant may be added to at least a part of the outer surface of the wallof the conduit.

The step of removing at least part of the masking agent from the outersurface of the wall of the conduit may be carried out by etching, plasmaetching, abrading, and/or ablating.

The step of removing at least a part of the masking agent may comprisethe step of applying a solvent to the masking agent. The solvent may bewater.

The method may comprise the step of removing substantially all of themasking agent from the conduit. The step of removing substantially allof the masking agent from the conduit may be carried out after the stepof adding the sealant to at least a part of the porous section of theconduit. The step of removing substantially all of the masking agent,when performed after the addition of the sealant to at least a part ofthe porous section of the conduit, may be carried out such that it doesnot result in the removal of the sealant from the conduit.

The step of removing substantially all of the masking agent may comprisethe step of applying a solvent to the masking agent. The solvent may bewater.

The step of removing at least a part of the masking agent may be carriedout at a temperature of between approximately 15° C. and approximately140° C., optionally between approximately 15° C. and approximately 95°C., optionally between approximately 35° C. and approximately 45° C.,optionally approximately 40° C. The step of removing at least a part ofthe masking agent may be carried out for between approximately 40minutes and approximately 300 minutes, optionally between approximately40 minutes and approximately 60 minutes, optionally betweenapproximately 45 minutes and approximately 55 minutes, optionally forapproximately 51 minutes.

The step of removing at least a part of the masking agent may be carriedout by applying gas to the conduit. The step of removing at least a partof the masking agent may be carried out by applying steam to theconduit. The step of removing at least a part of the masking agent maybe carried out in an autoclave.

The method may comprise the step of agitating the conduit. The step ofagitating the conduit may be carried out during any of the other stepsof the method. The step of removing at least part of the masking agentmay be carried out while agitating the conduit in a solution comprisinga solvent. The solvent may be water.

When applied to the conduit, the masking agent may form a masking agentlayer. The masking agent layer may be a polymer layer. The masking agentmay be applied to the conduit using a masking agent solution. The methodmay comprise the step of applying the masking agent solution to theconduit. The method may comprise the further step of removing solventfrom the masking agent solution.

The masking agent solution may comprise a solvent. The masking agentsolution may comprise a polar solvent. The masking agent solution maycomprise water.

The step of removing solvent from the masking agent solution may becarried out by evaporating solvent therefrom. The method may comprisethe further step of evaporating solvent from the masking agent solutionat a temperature of between approximately 15° C. and approximately 80°C., optionally between approximately 50° C. and approximately 80° C.

The masking agent may be added to the conduit by immersing the conduitin the masking agent. The masking agent may be added to the conduit byimmersing the conduit in the masking agent solution. The masking agentmay be added to the conduit by immersing the conduit in the maskingagent solution while agitating the conduit. The masking agent may beadded to the conduit by immersing the conduit in the masking agent, orin the masking agent solution, for up to approximately 1 minute. Themasking agent may be added to the conduit by immersing the conduit inthe masking agent, or in the masking agent solution, for up toapproximately 1 minute while agitating the conduit.

The masking agent may be added to the conduit by applying a maskingagent solution to the inner surface of the wall of the conduit. Themasking agent may be added to the conduit by applying a masking agentsolution to the outer surface of the wall of the conduit.

The masking agent may be added to the conduit by immersing the conduitin the masking agent, by dipping the conduit in the masking agent, byspray coating the masking agent onto the conduit, and/or by brushing themasking agent onto the conduit.

The masking agent solution may be added to the conduit by spraying themasking agent onto at least a part of the porous section of the conduit.

The masking agent may comprise polyvinylpyrrolidone (PVP). The maskingagent may comprise PVP having a molecular weight of betweenapproximately 6,000 g/mol and approximately 15,000 g/mol, optionallybetween approximately 8,000 g/mol and approximately 12,000 g/mol,optionally approximately 10,000 g/mol. The masking agent may compriseglycerol. The masking agent may comprise PVP and glycerol.

The masking agent may be water-soluble.

The masking agent solution may comprise PVP and water. The masking agentsolution may comprise PVP, glycerol and water.

The masking agent may comprise between approximately 3% w/v andapproximately 30% w/v of polymer in solution, optionally betweenapproximately 5% w/v and approximately 30% w/v of polymer in solution,optionally between approximately 5% w/v and approximately 20% w/v ofpolymer in solution, optionally between approximately 5% w/v andapproximately 10% w/v of polymer in solution, optionally betweenapproximately 5% w/v and approximately 7% w/v of polymer in solution,optionally approximately 7% w/v of polymer in solution, optionallyapproximately 6% w/v of polymer in solution, optionally approximately 5%w/v of polymer in solution, optionally approximately 4% w/v of polymerin solution, optionally approximately 3% w/v of polymer in solution. Themasking agent may comprise between approximately 3% w/v andapproximately 80% w/v of polymer in solution.

The masking agent solution may comprise between approximately 3% w/v ofPVP in solution and approximately 30% w/v of PVP in solution, optionallybetween approximately 5% w/v and approximately 30% w/v of PVP insolution, optionally between approximately 5% w/v and approximately 20%w/v of PVP in solution, optionally between approximately 5% w/v andapproximately 10% w/v of PVP in solution, optionally approximately 7%w/v of PVP in solution, optionally approximately 6% w/v of PVP insolution, optionally approximately 5% w/v of PVP in solution, optionallyapproximately 4% w/v of PVP in solution, optionally approximately 3% w/vof PVP in solution.

The masking agent solution may comprise approximately 1% w/v of glycerolin solution. The masking agent solution may comprise approximately 6%w/v of PVP in solution, and approximately 1% w/v of glycerol insolution. The ratio of glycerol to masking agent in the masking agentsolution may be between approximately 1 % and approximately 100 %. Theratio of glycerol to masking agent in the masking agent solution may bebetween approximately 1 % and approximately 30 %, optionally betweenapproximately 1.5 % and approximately 30 %, optionally betweenapproximately 5 % and approximately 30 %, optionally betweenapproximately 1 % and approximately 20 %, optionally betweenapproximately 1 % and approximately 15 %, and optionally betweenapproximately 1% and approximately 10%.

The masking agent may comprise methyl cellulose. The masking agent maycomprise poly(ethylene glycol) (PEG). The masking agent may comprise PEGhydrogel.

The masking agent may be made from a biocompatible material, or frombiocompatible materials. Applying the masking agent to the conduit mayform a biocompatible layer.

The terms biodegrade, biodegradable, bioabsorbable and bioresorbable areused herein to refer to materials which degrade over time when implantedin the human or animal body.

The masking agent may comprise a bioresorbable, or a biodegradablematerial. The masking agent may be biodegradable. The masking agent maybe configured to biodegrade when implanted inside a human or animalbody. The masking agent may be configured to bioresorb when implantedinside a human or animal body. The masking agent may be a biodegradablepolymer. The masking agent may comprise a biodegradable polymer. Themasking agent may be configurable to be biodegradable.

During the step of adding the masking agent to at least a part of theporous section of the conduit, the conduit may be moved from thecontracted state to the extended state. During the step of adding themasking agent to at least a part of the porous section of the conduit,the conduit may be moved from the extended state to the contractedstate. The step of adding the masking agent to at least a part of theporous section of the conduit may be carried out while the conduit ismoved between the contracted state and the extended state. The step ofadding the masking agent to at least a part of the porous section of theconduit may be carried out while the conduit is in the contracted state.The step of adding the masking agent to at least a part of the poroussection of the conduit may be carried out while the conduit is in theextended state. One or more of the steps of the method may be carriedout while the conduit is moved between the contracted state and theextended state.

The step of moving the conduit between the contracted state and theextended state may elongate the conduit by a factor of up toapproximately 100%. The step of moving the conduit between thecontracted state and the extended state may elongate the conduit by afactor of between approximately 45% and approximately 55%. The step ofmoving the conduit between the contracted state and the extended statemay elongate the conduit by a factor of approximately 50%. In thecontracted state, the length of the conduit may be reduced from itsfully extended length by a factor of between approximately 20% andapproximately 80%, optionally between approximately 20% andapproximately 40%, optionally between approximately 40% andapproximately 60%. In the extended state, the length of the conduit maybe reduced from its fully extended length by a factor of betweenapproximately 20% and approximately 80%, optionally betweenapproximately 20% and approximately 40%, optionally betweenapproximately 40% and approximately 60%.

The step of adding the masking agent to at least a part of the poroussection of the conduit may include providing gas to the conduit. The gasmay be configured to flow towards the outer surface of the wall of theconduit. In this arrangement, the step of adding the masking agent tothe conduit results in the masking agent being formed preferentially onthe inner surface of the wall of the conduit. In this arrangement, theouter surface of the wall of the conduit may remain substantially devoidof the masking agent. The gas may be air.

The sealant may be configured to substantially block the porous sectionof the conduit, such that the flow of fluid through the porous sectionof the conduit is mitigated. The sealant may be configured to prevent,or obviate, movement of fluid through the wall of the conduit. The fluidmay be blood.

The sealant may be added to at least a part of the outer surface of thewall of the conduit. The sealant may be added to substantially all ofthe outer surface of the wall of the conduit.

The method may be carried out such that the step of adding the sealantto at least a part of the porous section of the conduit does not resultin the removal of the masking agent. In this arrangement, the sealantand the masking agent are compatible with each other. That is, thesealant and the masking agent can be in contact with each other withouteither the sealant or the masking agent being damaged or, when appliedto the conduit, from being removed therefrom.

The sealant may be biocompatible. The sealant may be made from abiocompatible material, or from biocompatible materials. The sealant mayform a sealing layer. The sealing layer may be a biocompatible layer.The sealant may form a biocompatible layer.

The sealant may be a polymer. The sealing layer may be a polymer layer.The sealant may comprise polyurethane. The sealant may comprisethermoplastic polyurethane (TPU). The sealant may comprise silicone. Thesealant may comprise polyurethane and silicone. The sealant may compriseTPU and silicone. The sealant may comprise aliphatic polycarbonate. Thesealant may comprise polyurethane and aliphatic polycarbonate. Thesealant may comprise TPU and aliphatic polycarbonate. The sealant maycomprise room temperature vulcanising (RTV) silicone. The sealant maycomprise RTV silicone elastomer. The sealant may comprise polycarbonate.The sealant may comprise one or more thermoplastic elastomers.

The sealant solution may comprise polyurethane. The sealant solution maycomprise TPU. The sealant solution may comprise silicone. The sealantsolution may comprise polyurethane and silicone. The sealant solutionmay comprise TPU and silicone. The sealant solution may comprisealiphatic polycarbonate. The sealant solution may comprise polyurethaneand aliphatic polycarbonate. The sealant solution may comprise TPU andaliphatic polycarbonate. The sealant solution may comprise RTV silicone.The sealant solution may comprise RTV silicone elastomer. The sealantsolution may comprise polycarbonate. The sealant solution may compriseone or more thermoplastic elastomers.

The organic solvent may be an aprotic solvent. The organic solvent maybe a non-polar solvent. The sealant solution may comprise heptane. Thesealant solution may comprise xylene. The sealant solution may comprisesilicone and heptane. The sealant solution may comprise silicone andxylene. The sealant solution may comprise RTV silicone elastomer andheptane. The sealant solution may comprise RTV silicone elastomer andxylene. The sealant solution may comprise polyurethane and heptane. Thesealant solution may comprise polyurethane and xylene. The sealantsolution may comprise polycarbonate and heptane. The sealant solutionmay comprise polycarbonate and xylene.

The sealant solution may comprise a polar solvent. The sealant solutionmay comprise dimethylacetamide (DMAC). The sealant solution may comprisetetrahydrofuran (THF). The sealant solution may comprise TPU and DMAC.The sealant solution may comprise thermoplastic polyurethane and THF.

The sealant may be configurable to mitigate against environmental stresscracking. The sealant, when applied to the conduit may be configured tomitigate against environmental stress cracking.

The method may comprise the step of removing solvent from the sealant.The method may comprise the step of removing solvent from the sealantsolution. The step of removing solvent may be carried out by evaporatingsolvent from the sealant. The step of removing solvent may be carriedout by evaporating solvent from the sealant solution.

The sealant may be added to the conduit by brushing the sealant onto theconduit. The sealant may be added to the conduit by spray-coating thesealant onto the conduit. The sealant may be added to the conduit bydipping the conduit in the sealant. The sealant may be added to theconduit by casting the sealant onto the conduit. The sealant may beadded to the conduit by immersing the conduit in the sealant. Thesealant may be added by vapour deposition. The sealant may be added bychemical vapour deposition. The sealant may be added by electrostaticspinning and/or filament spinning. The sealant may be added to theconduit by wiping the sealant onto the conduit. The sealant may be addedto the conduit while the conduit is rotated about its longitudinal axis.The sealant may be added to the conduit while the conduit is rotatedabout its longitudinal axis at up to approximately 2,000 rpm, optionallybetween 700 rpm and 2,000 rpm, optionally between approximately 40 rpmand approximately 80 rpm, optionally at approximately 60 rpm.

Prior to applying the masking agent and the sealant, the surface of thetextile, medical textile or medical device (e.g. prosthesis) may besurface treated with an elastomer. The elastomer may be the sameelastomer as the sealant or it may be a different elastomer. Suchsurface treatment is designed to be a very light application of theelastomer to ensure that no elastomer penetrates through the wall of thetextile fabric. Such surface treatment may be applied by light surfacespraying, selective area coating or application of thin elastomericfibers prior to their cure. For example, spots of elastomer may beplaced along the length and radius. The purpose of surface treating isto ensure that the sealant will have a place to adhere in the event thatexcess masking agent unintentionally interferes with the sealant. Thesurface treatment will repel the masking agent, thus providing anattachment/adhesion site for the sealant.

The surface treatment may also be used to alter the properties of thetextile to, for example, promote adhesion of the sealing agent thereat.This may involve surface activation for altering chemical adhesionproperties on the textile for enhanced securement of the sealantthereat. Further, the hydrophilicity and/or hydrophobicity of portionsof the textile may also be modified for enhanced attraction and/orrepulsion of the masking agent(s) and/or sealants. Non-limitingtechniques may include, but are not limited to, the use of plasmageneration, including low pressure or vacuum generation, atmosphericpressure generation, elevated pressure generation, including forexample, glow discharge generation, corona discharge generation,dielectric-barrier discharge generation, and the like. Further,ultraviolet irradiation and laser treatments may be used. Suchpreconditioning before applying the masking agent and/or the sealant maypromote sealant attachment via physical and/or chemical modification ofthe textile substrate. Further, the textile patterns themselves may bemodified to include greater extents of floating yarns to provide araised yarn or velour surface to the textile where such raised yarnswill provide greater access points for sealant securement to the graft.

During the step of adding the sealant to the conduit, the conduit may bemoved from the contracted state to the extended state. During the stepof adding the sealant to the conduit, the conduit may be moved from theextended state to the contracted state. During the step of adding thesealant to the conduit, the conduit may be moved between the contractedstate and the extended state.

The step of adding the sealant to the conduit may be carried out, atleast in part, when the conduit is in the contracted state. The step ofadding the sealant to the conduit may be carried out, at least in part,when the conduit is in the extended state. The step of adding thesealant to the conduit may be carried out, at least in part, when theconduit is moved between the contracted state and the extended state.

The step of moving the conduit between the contracted state and theextended state may elongate the conduit by up to approximately 100%. Thestep of moving the conduit between the contracted state and the extendedstate may elongate the conduit by between approximately 45% andapproximately 55%. In the contracted state, the length of the conduitmay be reduced from its fully extended length by a factor of betweenapproximately 20% and approximately 80%, optionally betweenapproximately 20% and approximately 40%, optionally betweenapproximately 40% and approximately 60%. In the extended state, thelength of the conduit may be reduced from its fully extended length by afactor of between approximately 20% and approximately 80%, optionallybetween approximately 20% and approximately 40%, optionally betweenapproximately 40% and approximately 60%.

The sealant, once added to the conduit, may comprise betweenapproximately 4 mg per cm² and 19 mg per cm² of silicone, optionallyapproximately 8 mg per cm².

The method may comprise the further step of drying the vascularprosthesis. The further step of drying the vascular prosthesis may becarried out at a temperature of between approximately 15° C. toapproximately 45° C. The further step of drying the vascular prosthesismay be carried out after the step of removing at least part of themasking agent from the conduit. The further step of drying the vascularprosthesis may be carried out after the step of adding the sealant tothe conduit. The drying step may be configured to, at least in part,remove residual solvent, water, or the like, from the vascularprosthesis.

The further step of drying the vascular prosthesis may comprise the stepof providing gas to the vascular prosthesis. The gas may be air.

The method may comprise multiple drying steps.

The, or each, drying step may be carried out at a temperature of betweenapproximately 15° C. to approximately 45° C.

The method may comprise the step of weighing the conduit. The step ofweighing the conduit may be carried out prior to the step of adding themasking agent to the conduit. The step of weighing the conduit may becarried out prior to the step of adding the sealant to the conduit. Thestep of weighing the conduit may be used to determine, at least in part,the amount of masking agent to be applied to the conduit. The step ofweighing the conduit may be used to determine, at least in part, theamount of sealant to be applied to the conduit.

The method may comprise the step of measuring the length of the conduit.The measurement of the length of the conduit may be used, at least inpart, to determine the amount of masking agent to be added to theconduit. The measurement of the length of the conduit may be used, atleast in part, to determine the amount of sealant to be added to theconduit.

The weight of the conduit, and the length of the conduit, may be used,at least in part, to determine the amount of masking agent to be addedto the conduit. The weight of the conduit, and the length of theconduit, may be used, at least in part, to determine the amount ofsealant to be added to the conduit.

The support member may be added to the wall of the conduit. The supportmember may be added to the inner surface of the wall of the conduit. Thesupport member may be added to the inner surface and the outer surfaceof the wall of the conduit. The sealant may be configured to attach thesupport member to the conduit. In this arrangement, the support memberis added to the conduit and the sealant is then added to the conduit inorder to seal the conduit, and to attach the support member to theconduit.

The support member may be a cable, wire or the like. The support membermay comprise at least one of a polymer material, a metal material, ashape memory alloy, and a superelastic alloy. The support member maycomprise at least one of: polyethylene terephthalate,polytetrafluoroethylene, polyurethane, polycarbonate, silicone,stainless steel, titanium, nickel, and nickel titanium (Nitinol). Thesupport member may be a flexible member. The support member may becapable of being wrapped around the conduit. The support member may bearranged to nest between the crimps of the conduit. The support membermay be a flexible, polymer wire. The support member may be a metallic orpolymeric member, such as a shape memory metallic or polymeric member.The support member may be disposed at an inner portion of the conduit,at an outer portion of the conduit, within the textile wall of theconduit, and combinations thereof. The support member may be secured tothe conduit by the sealant, for example the sealant may encapsulate thesupport member or the support member may be embedded in the sealant. Insome embodiments, the support member may be secured to the conduit byother means, such as suturing, adhesive bonding, etc. The support membermay be arranged longitudinally, radially or a combination thereof, aboutthe conduit.

The support member may be biocompatible.

The vascular prosthesis may be connectable to one or more furtherprosthesis, or prostheses. The inlet of the vascular prosthesis may beconnectable to an outlet of a further prosthesis. The outlet of thevascular prosthesis may be connectable to an inlet of a furtherprosthesis. The vascular prosthesis may be connectable to one or moreheart valves, or synthetic heart valves. The vascular prosthesis may beconnectable to a cardiac assist device, a ventricular assist device, aleft ventricular assist device, and/or a right ventricular assistdevice, a biological heart valve, or the like. The further prosthesismay be a biological heart valve.

The vascular prosthesis may be connectable to one or more blood vessels.The vascular prosthesis may be connectable to one or more blood vesselsby way of suture(s).

The vascular prosthesis may be locatable between a first end and asecond end of a severed, or diseased, blood vessel. The inlet of thevascular prosthesis may be connectable to the first end of the severed,or diseased, blood vessel. The outlet of the vascular prosthesis may beconnectable to the second end of the severed, or diseased blood vessel.

The method may comprise the step of sterilising the vascular prosthesis.The step of sterilising the vascular prosthesis may be carried out byway of a gamma sterilisation process. The further step of sterilisingthe vascular prosthesis may be carried out by way of an electron beamsterilisation process. The further step of sterilising the vascularprosthesis may be carried out by way of ethylene oxide sterilisation.The method may comprise one or more sterilisation steps. The vascularprosthesis may be configured to be capable of being sterilised, suchthat the vascular prosthesis is not damaged or structurally altered bybeing sterilised. The step of sterilising the vascular prosthesis mayconfigure the vascular prosthesis to be suitable for implantation in thehuman or animal body.

According to a second aspect of the invention there is provided avascular prosthesis comprising:

-   a conduit comprising a wall, the wall of the conduit comprising an    inner surface and an outer surface, at least a section of the    conduit being porous;-   wherein at least a part of the porous section comprises a sealant    configured to mitigate movement of fluid through the wall of the    conduit; and-   wherein the inner surface of the wall of the conduit is    substantially devoid of the sealant.

The sealant may form a sealing layer on at least a part of the outersurface of the wall of the conduit.

The sealant may form a sealing layer on substantially all of the outersurface of the wall of the conduit.

Substantially all of the conduit may be porous.

The inner surface of the wall of the conduit may be configured topromote the ingrowth of biological tissue thereon.

The conduit may be a woven fibrous polymer conduit.

The sealant may form a sealing layer, the sealing layer being a polymerlayer.

The sealant may comprise at least one of: silicone, room temperaturevulcanising silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, and polycarbonate.

The sealant may be configured to mitigate movement of blood through thewall of the conduit.

The vascular prosthesis may be sterilised.

The vascular prosthesis may be sterilised by way of at least one of thefollowing: a gamma sterilisation process, an ethylene oxidesterilisation process, and an electron beam sterilisation process.

The conduit may be moveable between a contracted state and an extendedstate.

The conduit may comprise a support member.

The support member may be located substantially adjacent to the outersurface of the wall of the conduit.

The support member may be wrapped around the outer surface of the wallof the conduit.

The conduit may comprise a plurality of crimps, the support member beingarranged to nest between the plurality of crimps.

The sealant may be arranged to, at least in part, attach the supportmember to the conduit.

The support member may be a flexible, polymer member.

The conduit may be configured to have at least two sections havingsubstantially different amounts of sealant thereon.

Embodiments of the second aspect of the invention may include one ormore features of the first aspect of the invention or its embodiments.Similarly, embodiments of the first aspect of the invention may includeone or more features of the second aspect of the invention or itsembodiments.

According to a third aspect of the present invention there is provided akit of parts for manufacturing a vascular prosthesis, the kit of partscomprising:

-   (i) a conduit comprising a wall, the wall of the conduit comprising    an inner surface and an outer surface, at least a section of the    conduit being porous;-   (ii) a masking agent; and-   (iii) a sealant;

when applied to at least a part of the porous section of the conduit,the masking agent being configured to mitigate presence of the sealanton the inner surface of the conduit; andwhen applied to at least a partof the porous section of the conduit, the sealant being configured tomitigate movement of fluid through the wall of the conduit.

Addition of the sealant to at least a part of the porous section of theconduit may form a sealing layer on at least a part of the outer surfaceof the wall of the conduit.

Addition of the masking agent to at least a part of the porous sectionof the conduit may form a masking agent layer on at least part of theinner surface of the wall of the conduit.

Substantially all of the conduit may be porous.

The kit of parts may comprise a masking agent remover, the masking agentremover being operable to remove applied masking agent from the conduit.

The masking agent remover may comprise a solvent.

The solvent may comprise water.

The masking agent remover may be operable to remove applied maskingagent from the conduit at a temperature of between approximately 15° C.and approximately 140° C.

The kit of parts may comprise an abrading tool, the abrading tool beingoperable to remove applied masking agent from the conduit.

The inner surface of the wall of the conduit may be configured topromote the ingrowth of biological tissue thereon.

The masking agent may comprise a polymer.

The masking agent may comprise a water-soluble polymer.

The masking agent applied to the conduit may form a masking agent layer,the masking agent layer being a polymer layer.

The masking agent may comprise at least one of: polyvinylpyrrolidone,glycerol, methyl cellulose, and poly(ethylene glycol) hydrogel. Themasking agent may comprise at least one of: polyvinylpyrrolidone,glycerol, methyl cellulose, polyethylene oxide, and poly(ethyleneglycol) hydrogel, as well as biological products as further describedherein such as collagen and gelatine.

The masking agent may be biocompatible.

Masking agent applied to the conduit may form a biocompatible maskingagent layer.

The kit of parts may comprise a masking agent solution, the maskingagent solution being operable to apply masking agent to the conduit.

The masking agent solution may be a polymer solution.

The conduit may be immersible in the masking agent solution.

The masking agent solution may comprise between approximately 5% w/v ofpolymer in solution and approximately 30% w/v of polymer in solution.

When the masking agent and the sealant are applied to the conduit, thesealant may be configured such that addition of the sealant to theconduit does not result in the removal of the applied masking agent fromthe conduit.

The masking agent may be configured to biodegrade when implanted insidethe human or animal body.

The conduit may be a woven fibrous polymer conduit.

The sealant may comprise a polymer, optionally a water-insolublepolymer.

The sealant, when applied to the conduit, may form a sealing layer, thesealing layer being a polymer layer.

The sealant may comprise at least one of: silicone, room temperaturevulcanising silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, and polycarbonate.

The kit of parts may comprise a sealant solution operable to applysealant to the conduit.

The sealant solution may be a polymer solution.

The sealant solution may comprise an organic solvent.

The sealant solution may comprise at least one of heptane and xylene.

The kit of parts may comprise a sealant applicator operable to applysealant to the conduit, and/or a masking agent applicator operable toapply masking agent to the conduit.

The sealant applicator may be an apparatus for spray coating thesealant, and/or a brush, or the like.

The masking agent applicator may be a brush, an apparatus forspray-coating the masking agent, an apparatus for dipping or immersingthe conduit in the masking agent, and/or an apparatus for wiping themasking agent onto the conduit.

The sealant, when applied to at least a part of the porous section ofthe conduit, may be configured to mitigate movement of blood through thewall of the conduit.

The conduit may be moveable between a contracted state and an extendedstate.

The kit of parts may comprise a further prosthesis.

The further prosthesis may be at least one of: a biological heart valve,a synthetic heart valve, a cardiac assist device, and a ventricularassist device, or the like.

The kit of parts may comprise a weighing device and/or a device formeasuring the length of the conduit.

The kit of parts may comprise a gas flow apparatus operable to providegas flow to the conduit.

The gas may be air.

Embodiments of the third aspect of the invention may include one or morefeatures of the first and/or second aspects of the invention and/ortheir embodiments. Similarly, embodiments of the first and/or secondaspects of the invention may include one or more features of the thirdaspect of the invention and/or its embodiments.

According to a fourth aspect of the present invention, there is provideda method of manufacturing a vascular prosthesis according to the secondaspect of the present invention.

Embodiments of the fourth aspect of the invention may include one ormore features of the first, second and/or third aspects of the inventionand/or their embodiments. Similarly, embodiments of the first, secondand/or third aspects of the invention may include one or more featuresof the fourth aspect of the invention and/or its embodiments.

According to a fifth aspect of the present invention, there is provideda vascular prosthesis manufactured using the method of the first aspectof the present invention.

Embodiments of the fifth aspect of the invention may include one or morefeatures of the first, second, third and/or fourth aspects of theinvention and/or their embodiments. Similarly, embodiments of the first,second, third and/or fourth aspects of the invention may include one ormore features of the fifth aspect of the invention and/or itsembodiments.

According to a sixth aspect of the present invention, there is provideda vascular system, the vascular system comprising:

-   a vascular prosthesis manufactured according to the first aspect of    the invention; and-   a further prosthesis;

wherein the vascular prosthesis is connected to the further prosthesis,such that fluid can flow between the vascular prosthesis and the furtherprosthesis.

The further prosthesis may be at least one of: a biological heart valve,a synthetic heart valve, a cardiac assist device, and a ventricularassist device, or the like.

The further prosthesis may be a left ventricular assist device, a rightventricular assist device, and/or a synthetic heart valve, or the like.

Embodiments of the sixth aspect of the invention may include one or morefeatures of the first, second, third, fourth and/or fifth aspects of theinvention and/or their embodiments. Similarly, embodiments of the first,second, third, fourth, and/or fifth aspects of the invention may includeone or more features of the sixth aspect of the invention and/or itsembodiments.

According to a seventh aspect of the present invention, there isprovided a vascular system, the vascular system comprising:

-   a vascular prosthesis according to the second aspect of the    invention; and-   a further prosthesis;

wherein the vascular prosthesis is connected to the further prosthesis,such that fluid can flow between the vascular prosthesis and the furtherprosthesis.

The further prosthesis may be at least one of: a biological heart valve,a synthetic heart valve, a cardiac assist device, and a ventricularassist device, or the like.

The further prosthesis may be a left ventricular assist device, a rightventricular assist device, and/or a synthetic heart valve, or the like.

Embodiments of the seventh aspect of the invention may include one ormore features of the first, second, third, fourth, fifth and/or sixthaspects of the invention and/or their embodiments. Similarly,embodiments of the first, second, third, fourth, fifth and/or sixthaspects of the invention may include one or more features of the seventhaspect of the invention and/or its embodiments.

According to an eighth aspect of the invention there is provided amethod of implanting a vascular prosthesis, the method comprising thesteps of:

-   providing a vascular prosthesis manufactured according to the first    aspect of the invention;-   connecting an inlet of the vascular prosthesis to a first blood    vessel; and-   connecting an outlet of the vascular prosthesis to a second blood    vessel;

such that blood can flow between the first and second blood vesselsthrough the vascular prosthesis.

The first and second blood vessels may be formed from a blood vesselwhich is diseased, or has been severed, bisected, or the like.

Embodiments of the eighth aspect of the invention may include one ormore features of the first, second, third, fourth, fifth, sixth and/orseventh aspects of the invention and/or their embodiments. Similarly,embodiments of the first, second, third, fourth, fifth, sixth and/orseventh aspects of the invention may include one or more features of theeighth aspect of the invention and/or its embodiments.

According to a ninth aspect of the present invention, there is provideda method of implanting a vascular prosthesis, the method comprising thesteps of:

-   providing a vascular prosthesis according to the second aspect of    the invention;-   connecting the vascular prosthesis to a first blood vessel; and-   connecting the vascular prosthesis to a second blood vessel;

such that blood can flow between the first and second blood vesselsthrough the vascular prosthesis.

The first and second blood vessels may be formed from a blood vesselwhich is diseased, or has been severed, bisected, or the like.

Embodiments of the ninth aspect of the invention may include one or morefeatures of the first, second, third, fourth, fifth, sixth, seventhand/or eighth aspects of the invention and/or their embodiments.Similarly, embodiments of the first, second, third, fourth, fifth,sixth, seventh and/or eighth aspects of the invention may include one ormore features of the ninth aspect of the invention and/or itsembodiments.

According to a tenth aspect of the invention there is provided a methodof implanting a vascular system, the method comprising the steps of:

-   providing a vascular system, the vascular system comprising:    -   a vascular prosthesis manufactured according to the first aspect        of the invention; and    -   a further prosthesis;-   wherein the vascular prosthesis is connectable to the further    prosthesis;-   connecting the vascular prosthesis to the further prosthesis, such    that blood can flow therebetween;-   connecting an end of a blood vessel to the vascular prosthesis; and-   connecting the further prosthesis to the heart;

such that blood can flow between the blood vessel and the heart throughthe vascular system.

The further prosthesis may be a heart valve, a cardiac assist device,and/or a ventricular assist device, or the like. The further prosthesismay be a left ventricular assist device, a right ventricular assistdevice, and/or a synthetic heart valve, or the like.

Embodiments of the tenth aspect of the invention may include one or morefeatures of the first, second, third, fourth, fifth, sixth, seventh,eighth and/or ninth aspects of the invention and/or their embodiments.Similarly, embodiments of the first, second, third, fourth, fifth,sixth, seventh, eighth and/or ninth aspects of the invention may includeone or more features of the tenth aspect of the invention and/or itsembodiments.

According to an eleventh aspect of the invention there is provided amethod of implanting a vascular system, the method comprising the stepsof:

-   providing a vascular system, the vascular system comprising:    -   a vascular prosthesis according to the second aspect of the        invention; and    -   a further prosthesis;-   wherein the vascular prosthesis is connectable to the further    prosthesis;-   connecting the vascular prosthesis to the further prosthesis, such    that blood can flow therebetween;-   connecting an end of a blood vessel to the vascular prosthesis; and-   connecting the further prosthesis to the heart;

such that blood can flow between the blood vessel and the heart throughthe vascular system.

The further prosthesis may be at least one of: a biological heart valve,a synthetic heart valve, a cardiac assist device, and a ventricularassist device, or the like.

The further prosthesis may be a left ventricular assist device, a rightventricular assist device, and/or a synthetic heart valve, or the like.

Embodiments of the eleventh aspect of the invention may include one ormore features of the first, second, third, fourth, fifth, sixth,seventh, eighth, ninth and/or tenth aspects of the invention and/ortheir embodiments. Similarly, embodiments of the first, second, third,fourth, fifth, sixth, seventh, eighth, ninth and/or tenth aspects of theinvention may include one or more features of the eleventh aspect of theinvention and/or its embodiments.

According to a twelfth aspect of the invention there is provided amethod of manufacturing a vascular prosthesis, the method comprising thesteps of:

-   (i) providing a conduit comprising a wall, the wall of the conduit    comprising an inner surface and an outer surface, at least a section    of the conduit being porous; and-   (ii) adding a masking agent to at least a part of the porous    section;

wherein the masking agent is configured to mitigate movement of fluidthrough the wall of the conduit.

Embodiments of the twelfth aspect of the invention may include one ormore features of the first, second, third, fourth, fifth, sixth,seventh, eighth, ninth, tenth and/or eleventh aspects of the inventionand/or their embodiments. Similarly, embodiments of the first, second,third, fourth, fifth, sixth, seventh, eighth, ninth, tenth and/oreleventh aspects of the invention may include one or more features ofthe twelfth aspect of the invention and/or its embodiments.

According to a thirteenth aspect of the invention there is provided avascular prosthesis comprising:

-   a conduit comprising a wall, the wall of the conduit comprising an    inner surface and an outer surface, at least a section of the    conduit being porous;-   wherein at least a part of the porous section comprises a masking    agent configured to mitigate movement of fluid through the wall of    the conduit.

Embodiments of the thirteenth aspect of the invention may include one ormore features of the first, second, third, fourth, fifth, sixth,seventh, eighth, ninth, tenth, eleventh and/or twelfth aspects of theinvention and/or their embodiments. Similarly, embodiments of the first,second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth,eleventh and/or twelfth aspects of the invention may include one or morefeatures of the thirteenth aspect of the invention and/or itsembodiments.

In another aspect or embodiment, a method of manufacturing a tubulargraft may comprise the steps of: providing a textile comprising atubular wall disposed between a first open end and an opposed secondopen end, an inner surface and an opposed outer surface defining aninterior wall portion therein between, the tubular wall comprising atextile construction of one or more filaments or yarns, the textileconstruction by itself being permeable to liquid; applying asubstantially water-soluble material to at least a portion of thetubular wall; and applying a substantially water-insoluble syntheticsealant to at least a part of the outer surface of the tubular wall, thesubstantially water-insoluble synthetic sealant being configured tomitigate movement of fluid through the wall of the conduit; wherein thewater-soluble material is configured to mitigate penetration of thesealant to the inner surface of the conduit.

The step of applying the water-soluble material to at least a portion ofthe tubular wall may further comprise applying the water-solublematerial to at least a portion of the inner surface and a portion of theinterior portion of the tubular wall. The step of applying thewater-soluble material to at least a portion of the tubular wall mayfurther comprise applying the water-soluble material to at least aportion of the outer surface of the tubular wall.

The water-soluble material may be a solution of the water-solublematerial and a solvent. The solvent may be selected form the groupconsisting of water, lower alcohols, and combinations thereof. Thesolvent may be at least partially removed prior to applying thesubstantially water-insoluble synthetic sealant.

The method may further comprise removal of at least a portion of thewater-soluble material by dissolution, abrading, peeling, degrading, andcombinations thereof.

The water-soluble material may be selected from the group consisting ofpolyvinylpyrrolidone, glycerol, methyl cellulose, poly(ethylene glycol),poly(ethylene glycol) hydrogel, polyethylene oxide, collagen, albumin,gelatin, and combinations thereof. The water-soluble material may have amolecular weight from about 400 to about 1,000,000. The water-solublematerial may include plasticizers, such as but not limited topoly(ethylene glycol), polyethylene oxide, and the like.

The substantially water-insoluble synthetic sealant may be anelastomeric material selected from the group consisting of moisturecuring, light curing, thermo-curing, platinum catalysed, anaerobiccuring materials or a combination of these curing mechanisms. Theelastomeric material may be selected from the group consisting ofsilicones, polyurethanes, polycarbonates, thermoplastic elastomers, andcombinations thereof.

The one of more of the substantially water-soluble coating or thesubstantially water-insoluble coating may further comprise a componentselected from the group consisting of a colorant, a therapeutic agent, adye, and a fluorescent indicator.

The water-soluble material may comprise polyvinylpyrrolidone having amolecular weight of between approximately 6,000 g/mol and approximately15,000 g/mol.

The applying the water-soluble material may form layer on substantiallyall of the inner surface of the tubular wall.

The method may further comprise curing the substantially water-insolublesynthetic sealant.

The method may further comprise curing the substantially water-insolublesynthetic sealant; and thereafter removing at least a portion of thewater-soluble material. The method may further comprise removingsubstantially all of the water-soluble material from the inner surfaceof the tubular wall.

The method may further comprise: removing at least a part of thewater-soluble material from at least a part of the outer surface of thetubular wall prior to the applying the substantially water-insolublesynthetic sealant.

The removing of at least the portion of the water-soluble material maybe carried out at a temperature of between approximately 15° C. andapproximately 140° C.

The removing at least the portion of the water-soluble material mayfurther comprise the step of applying a solvent thereto. The solvent maycomprise water, lower alcohols, and combinations thereof.

The tubular textile may be agitated, rotated, spun, and shaken, or thelike, during the removal of the water-soluble material.

The removal of the water-soluble material may comprises dissolving,etching, plasma etching, ablating, abrading and combinations thereof ofthe water-soluble material.

The step of applying the water-soluble material may further comprisespraying the water-soluble material, brushing the water-solublematerial, immersing at least a portion of the tubular wall into asolution of the water-soluble material, and combinations thereof.

The substantially water-insoluble synthetic sealant may be a polymersolution. The polymer solution may comprise an organic solvent. Theorganic solvent may comprise at least one of heptane and xylene.

The substantially water-insoluble synthetic sealant may be applied bybrushing, spraying, roller coating the substantially water-insolublesynthetic sealant thereon.

The may further comprise one or more steps of selectively applying thesubstantially water-insoluble synthetic sealant to one or more portionsof the tubular wall, such that the tubular wall comprises at least twosections having substantially different amounts of the substantiallywater-insoluble synthetic sealant thereon.

The tubular wall having the coating of the substantially water-insolublesynthetic sealant may be, after curing thereof, substantiallyimpermeable to liquid. After curing of the substantially water-insolublesynthetic sealant, the tubular wall may have a water permeability ofabout 0.16 ml/min/cm² at 120 mm Hg pressure or less than 0.16 ml/min/cm²at 120 mm Hg pressure.

In another aspect or embodiment, a textile may comprise: a tubular walldisposed between a first open end and an opposed second open end andhaving an inner surface and an opposed outer surface, the tubular wallcomprising a textile construction of one or more filaments or yarns, thetextile construction by itself being permeable to liquid; wherein aportion of the inner surface comprises a coating of a substantiallywater-soluble material thereon; wherein the outer surface furthercomprises a coating of a substantially water-insoluble synthetic sealantdisposed thereon; and wherein the tubular wall having the coating of thesubstantially water-insoluble synthetic sealant is, after curingthereof, substantially impermeable to liquid.

The water-soluble material may be selected from the group consisting ofpolyvinylpyrrolidone, glycerol, methyl cellulose, poly(ethylene glycol),poly(ethylene glycol) hydrogel, polyethylene oxide, and combinationsthereof. The water-soluble material may have a molecular weight fromabout 400 to about 1,000,000.

The coating of the water-soluble material may comprise an oleophobiclayer.

The water-soluble material may comprise polyvinylpyrrolidone having amolecular weight of between approximately 6,000 g/mol and approximately15,000 g/mol.

The water-soluble material may comprise polyvinylpyrrolidone andglycerol.

The substantially water-insoluble synthetic sealant may be anelastomeric material selected from the group consisting of moisturecuring, light curing, thermo-curing, platinum catalyzed, anaerobiccuring materials or a combination of these curing mechanisms. Theelastomeric material may be selected from the group consisting ofsilicones, polyurethanes, polycarbonates, thermoplastic elastomers, andcombinations thereof.

One of more of the substantially water-soluble coating or thesubstantially water-insoluble coating may comprise a component selectedfrom the group consisting of a colorant, a therapeutic agent, a dye, anda fluorescent indicator.

After curing of the substantially water-insoluble synthetic sealant, thetubular wall may have a water permeability of about 0.16 ml/min/cm² at120 mm Hg pressure or less than 0.16 ml/min/cm² at 120 mm Hg pressure.

The textile construction may be selected from the group consisting of aweave of the one or more filaments or yarns, a knit of the one or morefilaments or yarns, a braid of the one or more filaments or yarns, and aweb of the one or more filaments or yarns.

The tubular wall may be a crimped wall having a series of peaks andvalleys. The substantially water-insoluble synthetic sealant may bedisposed at about 8 mg/cm² of area of the tubular wall or greater than 8mg/cm² of area of the tubular wall.

The tubular wall may be a non-crimped wall being substantially free ofpeaks and valleys. The substantially water-insoluble synthetic sealantmay be disposed at about 4 mg/cm² of area of the tubular wall or greaterthan 4 mg/cm² of area of the tubular wall.

The substantially water-insoluble synthetic sealant may be disposed atabout 14 mg/cm² of area of the tubular wall or less than 14 mg/cm² ofarea of the tubular wall.

The textile may include one portion of the tubular wall has a firstlevel of the substantially water-insoluble synthetic sealant to providea first soft, flexible zone; and another portion of the tubular wall hasa second level of the substantially water-insoluble synthetic sealant toprovide a second zone stiffer than the first zone; where the secondlevel the substantially water-insoluble synthetic sealant is greaterthan the first level of the substantially water-insoluble syntheticsealant.

Different zones may be created along the length of the device (e.g.prosthesis or graft) and engineered to accommodate a variety ofapplications and body architecture. For example, a particular need mayexist for the device to be turned, curved or twisted in order toproperly perform its function in the body, as well as to the physiologyof the patient. Tortuous pathways are often present in the body and themedical devices of the present invention are able to accommodate forsuch areas. The present disclosure and all of its embodiments allow forthe creation of such zones by the creation of one or more sealant layerson all of, or at portions of, the graft, and also by the incorporationof support members as described further herein, which as discussed maybe adhered to or embedded in the sealant material. As discussed, thesupport members may be polymeric or metallic and may be in a variety offorms such as elongate members, coils, wraps, rings or a combination ofsuch forms. An important feature of all embodiments of the invention isthat the sealant material is capable of serving as a foundational layerfor further coatings or for support members due to the excellentadherence of the base sealant layer to its graft substrate.

Additionally, the present invention and its various embodimentscontemplates the tailoring of the sealant surface such that itscoefficient of friction may be varied and desirably sufficiently lowsuch that the sealant does not stick to itself and/or sufficiently lowenough that when used in devices such as endovascular devices, hassufficient lubricity to facilitate delivery and deployment in the body,For example, the sealant surface desirably slides into delivery sheaths,slides across itself and does not stick to itself, to other portions ofthe device, other devices or the body. Such surface properties may beimparted by altering the sealant surface chemically or physically withlubricous groups or coatings to provide the desired coefficient offriction properties desired. Such surface properties may be in additionto the other properties the sealant possesses in the present invention.

At least a portion of the coating of the substantially water-insolublesynthetic sealant may engage at least a portion of the one or morefilaments or yarns.

The textile structure may be an implantable medical device. Theimplantable medical device may be selected from the group consisting ofsurgical vascular grafts, and endovascular grafts, ventricular assistdevices, artificial heart conduits, meshes, patches, hernia plugs,vascular wraps, heart valves, filters, and the like.

The textile structure may be a delivery medical device, such as acatheter.

In another embodiment, a textile structure may comprise: a fluidpermeable polymeric textile layer having opposing first and secondsurfaces and a length; a cross-linkable water-insoluble syntheticelastomeric layer on the first textile surface configured to render theliquid permeable polymeric textile layer substantially impermeable tofluid when cured; a substantially dried water-soluble polymer layer onthe second textile surface; wherein water-soluble polymer layersubstantially inhibits migration of the water-insoluble syntheticelastomeric layer onto the second surface; and wherein the water-solublepolymer layer is substantially removable by exposure to water.

In another embodiment, a textile structure may comprise: a fluidpermeable polymeric textile layer having opposing first and secondsurfaces and a length; a cross-linkable water-insoluble syntheticelastomeric layer on the first textile surface configured to render theliquid permeable polymeric textile layer substantially impermeable tofluid when cured; a substantially dried water-soluble polymer layer onthe second textile surface; wherein water-soluble polymer layersubstantially inhibits migration of the water-insoluble syntheticelastomeric layer onto the second surface; and wherein the water-solublepolymer layer is substantially removable by exposure to water. Theweight ratio of the cross-linkable water-insoluble elastomeric polymerto the water-soluble polymer may be from about 0.1:1 to about 100:1,including from about 1:1 to about 20:1.

In another embodiment, a textile structure may comprise: a fluidpermeable polymeric textile layer having opposing first and secondsurfaces and a length; a crosslinked water-insoluble elastomeric polymerlayer on the first textile surface forming a substantially fluidimpermeable barrier, wherein the crosslinked water-insoluble elastomericlayer is adhered to the first textile surface by elastomeric shrinkage;a water dissolvable polymer layer dried on the second textile surface;wherein the weight ratio of the crosslinked water-insoluble elastomericpolymer to the water dissolvable polymer may be from about 0.1:1 toabout 100:1. The weight ratio of the crosslinked water-insolubleelastomeric polymer to the water dissolvable polymer may be from about1:1 to about 20:1.

In another embodiment, a graft may comprise: a tubular wall disposedbetween a first open end and an opposed second open end and having aninner surface and an opposed outer surface, the tubular wall comprisinga textile construction of one or more filaments or yarns; wherein theouter surface comprises a coating or layer of a substantiallywater-insoluble sealant disposed thereon; wherein the inner surface issubstantially free of the substantially water-insoluble sealant; andwherein the tubular wall has a water permeability of about 0.16ml/min/cm² at 120 mm Hg pressure or less than 0.16 ml/min/cm² at 120 mmHg pressure. The textile construction may be selected from the groupconsisting of a weave of the one or more filaments or yarns, a knit ofthe one or more filaments or yarns, a braid of the one or more filamentsor yarns, and a web of the one or more filaments or yarns.

The coating or layer may be disposed within an intermediate portion ofthe tubular wall between the inner surface and the opposed outersurface.

The tubular wall may be a crimped wall having a series of peaks andvalleys. The substantially water-insoluble sealant may be disposed atabout 8 mg/cm² of area of the tubular wall or greater than 8 mg/cm² ofarea of the tubular wall.

The tubular wall may be a non-crimped wall being substantially free ofpeaks and valleys. The substantially water-insoluble sealant may bedisposed at about 4 mg/cm² of area of the tubular wall or greater than 4mg/cm² of area of the tubular wall.

The substantially water-insoluble sealant may be disposed at about 14mg/cm² of area of the tubular wall or less than 14 mg/cm² of area of thetubular wall.

The substantially water-insoluble sealant may be an elastomeric materialselected from the group consisting of moisture curing, light curing,thermo-curing, platinum catalyzed, anaerobic curing materials or acombination of these curing mechanisms. The elastomeric material may beselected from the group consisting of silicones, polyurethanes,polycarbonates, thermoplastic elastomers, and combinations thereof.

One of more of the substantially water-soluble coating (masking agentcoating or layer) or the substantially water-insoluble coating (sealantcoating or layer) may comprise a component selected from the groupconsisting of a colorant, a therapeutic agent, a dye, and a fluorescentindicator.

The substantially water-insoluble sealant (sealant coating or layer) maybe selected from the group consisting of silicone, room temperaturevulcanizing silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, polycarbonate, andcombinations thereof.

The graft may include one portion of the tubular wall having a firstamount of the substantially water-insoluble sealant (sealant coating orlayer) to provide a first soft, flexible zone; and another portion ofthe tubular wall having a second amount of the substantiallywater-insoluble sealant (sealant coating or layer) to provide a secondzone stiffer than the first zone; wherein the second amount of thesubstantially water-insoluble sealant (sealant coating or layer) isgreater than the first amount of the substantially water-insolublesealant (sealant coating or layer). The graft may include multipleregions having pluralities of soft, flexible zones and stiffer zones.The different zones may serve as foundations for building engineeredstructures onto a graft.

In another embodiment, an implantable or deliverable medical textile maycomprise: a wall having a textile construction and having a firstsurface and an opposed second surface; wherein the second surfacecomprises a coating of a substantially water-insoluble sealant disposedthereon; wherein the first surface is substantially free of thesubstantially water-insoluble sealant; and wherein the wall has a waterpermeability of about 0.16 ml/min/cm² at 120 mm Hg pressure or less than0.16 ml/min/cm² at 120 mm Hg pressure.

An assembly for producing an implantable or deliverable medical textilehaving a selectively applied water-insoluble sealant layer and/or aselectively applied water-soluble masking agent layer comprises amandrel having a length, a hollow lumen disposed within a portion of thelength, at least one open end, and a plurality of perforations through awall of the mandrel; a reservoir in fluid communication with the openlumen of the mandrel; and a water-soluble polymer disposed within thereservoir. The assembly may further comprise a tubular graft securablydisposed over a portion of the mandrel having the plurality ofperforations. The assembly may further comprise a vacuum source in fluidcommunication with the hollow lumen of the mandrel, and a manifoldconfigured to provide selective fluid communication between the hollowlumen of the mandrel and the reservoir and/or the vacuum source. Theassembly may further comprise a source of pressurized and/or blown airwhich is in fluid communication with the hollow lumen of the mandrel.

Embodiments of the present invention, however, are not limited tovascular prostheses, and the methods, coatings and masking agents maysuitably be used with other textile products, including medical andnon-medical textile products, such as but not limited to clothing,geotextiles, transportation textiles, military and/or defense textiles,safety and/or protective textiles, sports and/or recreation textiles,and the like. Further, textile products are not limited to tubularconduits, but may be of any shape including, but not limited to forexample, sheets, tapes, or even three dimensional shaped products.

In another aspect or embodiment of the present invention, a method formanufacturing a substantially impermeable textile graft comprises:providing a textile graft having a first surface and an opposed secondsurface; providing a water soluble masking agent comprisingpolyvinylpyrrolidone and glycerol without mixing or combining thepolyvinylpyrrolidone and the glycerol with added water; applying thewater soluble masking agent to a portion of the first surface of thetextile graft; providing a water insoluble sealing agent; maintainingthe second surface of the textile graft receptive for receiving thewater insoluble sealing agent; and applying the water insoluble sealingagent to the second surface of the textile graft. The water solublemasking agent may consist essentially of polyvinylpyrrolidone andglycerol. The water soluble masking agent may comprise from about 25 %w/w of the polyvinylpyrrolidone in the glycerol to about 75 % w/w of thepolyvinylpyrrolidone in glycerol, including from about 30 % w/w of thepolyvinylpyrrolidone in the glycerol to about 70 % w/w of thepolyvinylpyrrolidone in glycerol, including from about 40 % w/w of thepolyvinylpyrrolidone in the glycerol to about 60 % w/w of thepolyvinylpyrrolidone in glycerol, more desirably including from about 45% w/w of the polyvinylpyrrolidone in the glycerol to about 55 % w/w ofthe polyvinylpyrrolidone in glycerol, in particular about 50 % w/w ofthe polyvinylpyrrolidone in the glycerol. The water soluble maskingagent may be flowable. The water soluble masking agent may be preparedby dissolving the polyvinylpyrrolidone in the glycerol. Thepolyvinylpyrrolidone may be dissolved into the glycerol with one or moreof stirring and application of heat. The step of maintaining the secondsurface of the textile graft receptive for receiving the water insolublesealing agent may comprise preventing egress of the water solublemasking agent from the first surface to the second surface. The step ofpreventing the egress of the water soluble masking agent from the firstsurface to the second surface may comprise substantially prohibitingwicking of the water soluble masking agent from the first surface to thesecond surface. The step of maintaining the second surface of thetextile graft receptive for receiving the water insoluble sealing agentmay comprise removal of the water soluble masking agent from the secondsurface. The step of removal of the water soluble masking agent from thesecond surface may comprise dissolving the water soluble masking agentfrom the second surface. The step of removal of the water solublemasking agent from the second surface may comprise ablating the watersoluble masking agent from the second surface. The polyvinylpyrrolidonemay have a molecular weight of from about 2,500 g/mol to about 55,000g/mol, including from about 3,500 g/mol to about 50,000 g/mol, fromabout 5,000 g/mol to about 40,000 g/mol, from about 5,000 g/mol to about30,000 g/mol, from about 5,000 g/mol to about 20,000 g/mol, anddesirably from about 8,000 g/mol to about 10,000 g/mol. The waterinsoluble sealing agent may comprise a material selected from the groupconsisting of silicones, polyurethanes, polycarbonates, thermoplasticelastomers, and combinations thereof. The step of applying the waterinsoluble sealing agent to the second surface of the textile graft maycomprise spraying water insoluble sealing agent onto the second surfaceof the textile graft. The spraying may be forced air spraying orultrasonic assisted forced air spraying. The method may further compriseremoving the water soluble masking agent after the step of applying thewater insoluble sealing agent. The may further comprise curing the waterinsoluble sealing agent. After curing of the water insoluble sealingagent, the textile graft may be substantially impermeable to liquid.After curing of the water insoluble sealing agent, the textile graft mayhave a water permeability of about 0.16 ml/min/cm² at 120 mm Hg pressureor less than 0.16 ml/min/cm² at 120 mm Hg pressure. The textile graftmay be a tubular textile graft. The water soluble masking agent may havea viscosity from about 2,000 centipoise at room temperature to about100,000 centipoise at room temperature, including from about 50,000centipoise at room temperature to about 100,000 centipoise at roomtemperature. A textile graft made by these methods.

In another aspect or embodiment, a method for manufacturing ansubstantially impermeable textile graft may comprise: providing atextile graft having a first surface and an opposed second surface;providing a water soluble masking agent selected from the groupconsisting of polyvinylpyrrolidone, glycerol, methyl cellulose,poly(ethylene glycol), poly(ethylene glycol) hydrogel, polyethyleneoxide, and combinations thereof; applying the water soluble maskingagent to a portion of the first surface of the textile graft, wherein aportion of the water insoluble sealing agent is optionally disposed onthe second surface of the textile graft; ablating a portion of the watersoluble masking agent from the second surface of the textile graft;providing a water insoluble sealing agent selected from the groupconsisting of silicones, polyurethanes, polycarbonates, thermoplasticelastomers, and combinations thereof; and applying the water insolublesealing agent to the second surface of the textile graft. The step ofablating may further comprise providing a flow of solid particulatesagainst the second surface of the textile graft. The solid particulatesmay be a material selected from the group consisting of sodiumbicarbonate, sodium chloride, sugar, magnesium sulphate, potassiumchloride, and combinations thereof. The solid particulates have anaverage particle size across there largest dimension from about 50microns to about 300 microns. The solid particulates may have a Moh’shardness from about 1 to about 4. The solid particulates may be sprayedat a pressure from about 10 psig to about 50 psig. Solid particlesremaining on the graft may be removed, if desired, by any suitabletechnique. For example, solid particles ma be removed by vacuuming,washing, such as solvent washing, including washing with n-heptane.Washing may also be performed in an ultrasonic solvent bath. The methodmay further comprise curing the water insoluble sealing agent. Aftercuring of the water insoluble sealing agent, the textile graft may besubstantially impermeable to liquid. After curing of the water insolublesealing agent, the textile graft may have a water permeability of about0.16 ml/min/cm² at 120 mm Hg pressure or less than 0.16 ml/min/cm² at120 mm Hg pressure. The method may further comprise removing the watersoluble masking agent after the step of applying the water insolublesealing agent. The method may further comprise adding a dye to the waterinsoluble sealing agent. The method may further comprise adding a dye tothe water soluble masking agent. A textile graft made by these methods.

The masking agent may be applied to the graft prior to the applicationof the sealant composition. The present invention, however, is not solimited. For example, the masking agent and the sealant composition maybe applied concurrently or substantially concurrently. Moreover, themasking agent may be formulated to minimize its wicking potential amongor between yarns. One non-limiting example to minimize wicking potentialof the masking agent is to use a high viscous and/or high surfacetension masking agent formulation, such as masking agent components inglycerol with the separate addition of water. As such a masking agent isviscous, it may be heated during application to a graft, in particularto the application to one surface, such as to an inner or luminalsurface of the graft. The heat may be moderate as viscosity decreaseswith increasing temperature. The opposed surface of the graft may besubjected to cooling, such as application of cold or cool air. The lowertemperature will increase the viscosity of the masking agent, therebyacting as a barrier against migration of the masking agent towards theouter or opposed surface. The application of the cooling medium may bedone with concurrent or substantially concurrent application of thesealant agent to the outer or opposed surface, or may be done prior tothe application of the sealant agent. One non-limiting method for theconcurrent or substantially concurrent application of the masking agentand sealant formulation may be the use of spray nozzles, or the like,for applying the masking agent to the inner surface of the graft withone or more spray nozzles and applying the sealant agent to the outersurface of the graft with one or more different spray nozzles, or thelike. Spraying may include ultrasonic spraying. This may be especiallybeneficial for spraying of viscous fluids. Moreover, the textile graftmay be rotated while applying either masking agent and/or the sealantagent. Such controlled rotation prevents potential pooling, especiallyfor the masking agent, and provides for uniformity of the appliedmasking agent and/or the sealant agent.

In another aspect or embodiment, a method of providing a sealant to atextile graft may comprise: providing a textile graft having a firstsurface and an opposed second surface and having a textile pattern ofyarns inter-engaging yarns and interstices between or in the yarns;providing a water soluble masking agent selected from the groupconsisting of polyvinylpyrrolidone, glycerol, methyl cellulose,poly(ethylene glycol), poly(ethylene glycol) hydrogel, polyethyleneoxide, and combinations thereof; applying the water soluble maskingagent to at least a portion of the first surface of the textile graft,wherein a portion of the water soluble masking agent is further disposedat a plurality of the interstices; providing a water insoluble sealingagent selected from the group consisting of silicones, polyurethanes,polycarbonates, thermoplastic elastomers, and combinations thereof; andapplying the water insoluble sealing agent to the second surface of thetextile graft and over the portion of the water soluble masking agentbeing disposed at a plurality of the interstices; whereby the waterinsoluble sealing agent spreads over the water soluble masking agent toprovide one or more of the following: a substantially homogenous layerof the water insoluble sealing agent; a substantially uniform anduninterrupted coating of the water insoluble sealing agent; a layer ofwater insoluble sealing agent having a substantially uniform weight pergiven area of application; a substantially liquid impermeable barrier tothe underlying textile graft surface; a substantially lower force toextend a graft coated with the water insoluble sealing agent as comparedto comparable grafts which have not used a masking agent; asubstantially less amount of water insoluble sealing agent to provide asubstantially liquid impermeable barrier to the underlying textile graftsurface as compared to comparable grafts which have not used a maskingagent; and combinations thereof. The method may further compriseremoving the water soluble masking agent after the step of applying thewater insoluble sealing agent. The method may further comprise curingthe water insoluble sealing agent. After curing of the water insolublesealing agent, the water insoluble sealing agent may be disposed overthe interstices between and in the yarns. The textile graft may besubstantially impermeable to liquid. After curing of the water insolublesealing agent, the textile graft may have a water permeability of about0.16 ml/min/cm² at 120 mm Hg pressure or less than 0.16 ml/min/cm² at120 mm Hg pressure. A textile graft made by these methods.

In another aspect or embodiment, a method of sealing a textile graft maycomprise: applying a coating of a substantially water soluble maskingagent, having a viscosity of from about 2,000 centipoise at roomtemperature to about 100,000 centipoise at room temperature, to at leasta portion of a luminal surface of the textile graft, wherein a portionof the water soluble masking agent is further disposed at a plurality ofinterstices in the graft; and applying a water insoluble sealing agentto an outer graft surface opposing the luminal surface of the graft;wherein the water soluble masking agent causes one or more of thefollowing to occur: a substantially homogenous layer of the waterinsoluble sealing agent is formed; a substantially uniform anduninterrupted coating of the water insoluble sealing agent is formed; alayer of water insoluble sealing agent having a substantially uniformweight per given area of application; a substantially liquid impermeablebarrier to the underlying textile graft surface; a substantially lowerforce to extend a graft coated with the water insoluble sealing agent ascompared to comparable grafts which have not used a masking agent; asubstantially less amount of water insoluble sealing agent to provide asubstantially liquid impermeable barrier to the underlying textile graftsurface as compared to comparable grafts which have not used a maskingagent; and combinations thereof.

Embodiments of the various aspects of the invention as recited hereinmay include one or more features of other aspects of the inventionand/or their embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example,with reference to the drawings, in which:

FIG. 1 a depicts perspective views of a conduit from both inlet andoutlet perspectives according to an embodiment of the invention;

FIG. 1 b depicts perspective views of the conduit of FIG. 1 a after theaddition of a masking agent;

FIG. 1 c depicts perspective views of the conduit of FIG. 1 b after theaddition of a sealant;

FIG. 1 d depicts perspective views of the conduit of FIG. 1 c afterremoval of substantially all of the masking agent;

FIGS. 2 a and 2 b show a detailed view of an inner surface of a wall ofthe conduit of FIG. 1 a ;

FIGS. 3 a and 3 b shows detailed view of the inner surface of the wallof the conduit of FIG. 1 b after the addition of the masking agent;

FIG. 4 a shows a detailed view of the inner surface of the wall of theconduit of FIG. 1 d ;

FIG. 4 b shows a detailed view of the inner surface of the wall of theconduit of FIG. 1 d ;

FIG. 5 a shows a detailed view of the outer surface of the wall of theconduit of FIG. 1 d ;

FIG. 5 b shows a detailed view of the outer surface of the wall of theconduit of FIG. 1 d ;

FIG. 6 a shows a detailed view of the outer surface of the wall of theconduit of FIG. 1 d ;

FIG. 6 b shows a detailed view of the inner surface of the wall of theconduit of FIG. 1 d ;

FIG. 7 depicts the addition of a support member to the conduit showndepicted in FIG. 1 a ;

FIG. 8 depicts an alternative embodiment of a conduit manufacturedaccording to the process of FIGS. 1 a to 1 d ;

FIG. 9 a is a perspective view of a hollow and perforated mandrel foruse with the present invention;

FIG. 9 b is a cross-section view of the mandrel of FIG. 9 a taken alongthe 9b-9b axis showing a hollow lumen passageway through the mandrel;

FIG. 9 c is a partial cutaway view of the wall of the mandrel of FIG. 9a taken along the 9c-9c axis showing perforations or holes through themandrel wall;

FIG. 10 a is a photograph of a cross-section of a textile graft of thepresent invention showing sealing layer or coating on outer surfaceportions of the textile graft and showing the inner surface portions ofthe textile graft being substantially free of any sealing layer orcoating;

FIG. 10 b is a photograph of a portion of the inner surface of thetextile graft of FIG. 10 a showing the inner surface portion of thetextile graft being substantially free of any sealing layer or coating;

FIG. 10 c is a photograph of a portion of the outer surface of thetextile graft of FIG. 10 a showing the outer surface portion of thetextile graft being substantially covered with the sealing layer orcoating;

FIG. 11 is a photograph of a dried 40% PVP masking agent concentrationapplied to a graft sample;

FIG. 12 is a scanning electron microscope (SEM) photograph of across-sectional section of textile sample 2, which is described below inconjunction with Tables 10-14;

FIG. 13 is a SEM photograph of an inner surface of textile sample 2,which is described below in conjunction with Tables 10-14;

FIG. 14 is a SEM photograph of a cross-sectional section of textilesample 9, which is described below in conjunction with Tables 10-14;

FIG. 15 is a SEM photograph of an inner surface of textile sample 9,which is described below in conjunction with Tables 10-14;

FIGS. 16-18 are SEM photographs of cross-sectional sections of textilesample 7, which is described below in conjunction with Tables 10-14; and

FIG. 19 is a SEM photograph of a cross-sectional section of textilesample 15, which is described below in conjunction with Tables 10-14.

FIG. 20 is a graft showing force-to-extend test values for grafts of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein the term “substantially” and its equivalents refer tobeing at least 70% of a stated value, desirably within at least 80% of astated value, and more desirably within 90% or 95% of a stated value.

As used herein the terms “about” or “approximate” and their equivalentsrefer to being within (plus and/or minus) at least 20% of a statedvalue, desirably within at least 10% of a stated value, and moredesirably within 5% of a stated value.

As used herein the terms “layer” and “coating” may be usedinterchangeably to refer to a deposition of material over, underneath,or within a substrate, such as a textile substrate.

As used herein masking agent shall refer to any suitable non-biological,e.g., synthetic, hydrophilic polymer and any suitable biologicalhydrophilic polymer. However, it should be understood that other maskingagents may be used.

With reference to FIGS. 1 a to 1 d , four stages of manufacture of avascular prosthesis 16 are illustrated. In each of the FIGS. 1 a to 1 dtwo perspective views of the conduit 10 and/or the vascular prosthesis16 are provided. The left hand views show an inlet 10 c being forwardlydisposed in the views, and the right hand views show an outlet 10 dbeing forwardly disposed in the views.

FIG. 1 a shows a conduit 10 which is suitable for implant in the humanor animal body. The conduit 10 is a cylindrical conduit 10 and comprisesa wall 10 f. The wall 10f comprises an inner surface 10 a and an outersurface 10 b. The conduit 10 also comprises an inlet 10 c and an outlet10 d. In the embodiment described here, substantially all of the conduit10 is porous 10 e. However, it should be understood that at least asection of the conduit 10 could be porous 10 e. In this embodiment, theconduit 10 is a woven, fibrous polymer conduit 10. The woven nature ofthe conduit 10 leads to substantially all of the conduit 10 being porous10 e.

The conduit 10 comprises polyethylene terephthalate (PET). However, itshould be understood that the conduit 10 could comprise other materials,such as polytetrafluoroethylene (PTFE). Other suitable polymers formedical textile applications may include, but are not limited topolyolefin, polyester, poly(ether amide), poly(ether ester), poly(etherurethane), poly(ester urethane),poly(ethylene-styrene/butylene-styrene), and other block copolymers.

In the embodiment illustrated and described here, the weft yarnpick-rate of the conduit 10 is approximately 45 ppcm. However, it shouldbe understood that the weft yarn pick-rate of the conduit 10 could bebetween approximately 25 ppcm and approximately 50 ppcm.

The conduit 10 is moveable between a contracted state and an extendedstate.

FIG. 1 a thus depicts an unprocessed conduit 10. In its unprocessedform, blood (an example of a fluid) can flow between the outer surface10 b of the wall 10 f and the inner surface 10 a of the wall 10 f. Thatis, if fluid flows into the inlet 10 c, the blood will leak through theporous section 10 e of the conduit 10. The conduit 10 depicted in FIG. 1a must therefore be sealed prior to use as an implantable vascularprosthesis 16.

The conduit 10 depicted in FIG. 1 a has been cut to a predeterminedsize. For example, the length of the conduit 10 may need to be altereddepending on the size of vascular prosthesis 16 required. Furthermore,if the vascular prosthesis 16 is to be connected to at least one heartassist component (an example of a further prosthesis), this may alsorequire a different size, or length of conduit 10 to be used. Theconduit 10 is also weighed during this step of the manufacturingprocess.

In the embodiment illustrated here, the conduit 10 has a substantiallyuniform cross section throughout. However, it should be understood thatthe conduit 10 could have an irregular cross section throughout. Forexample, if the conduit 10 is to be connected between a furtherprosthesis, such as a heart valve, and an end of a severed blood vessel,the conduit 10 could have an irregular cross section throughout. Asdescribed in more detail below, in some embodiments the conduit 10 couldbe configured to have differing degrees of flexibility, either byselectively adding sealant 14 to different sections of the conduit 10,or in other ways.

As described above, it is desirable for the inner surface 10 a of thewall 10 f of the conduit 10 to remain free from, or substantially devoidof, the material used to seal the conduit 10. The reason for this is toensure that the inner surface 10 a of the wall 10 f of the conduit 10,remains of a porous 10 e, woven nature, to ensure that when the vascularprosthesis 16 is implanted in the human or animal body, biologicaltissue will grow into the inner surface 10 a of the wall 10 f of theconduit 10. This is important to ensure that ingrowing biological tissueforms a pseudointima (an example of an inner biological tissue layerwithin a vascular prosthesis). Furthermore, in addition to the promotionof biological tissue growth on the inner surface 10 a of the wall 10 fof the conduit 10, it is also advantageous if the biological tissuelayer growing on the inner surface 10 a of the wall 10 f of the conduit10 has good adhesion to the inner surface 10 a. If the adhesion betweenthe biological tissue layer and the inner surface 10a is insufficient,complications can arise such as haemorrhagic dissection.

FIG. 1 b shows the conduit 10 after the addition of a masking agent 12.In this embodiment, the masking agent 12 forms a masking agent layer onthe inner surface 10 a of the wall 10 f of the conduit 10. The maskingagent layer is designed to protect the inner surface 10 a of the conduit10 during the manufacturing process illustrated and described herein.Specifically, the masking agent 12 is designed to mitigate presence ofsealant 14 on the inner surface 10 a of the wall 10 f of the conduit 10.

Prior to the addition of the masking agent 12 to the conduit 10, theconduit 10 is weighed. The weight of the conduit 10 is then used, atleast in part, to determine the amount of masking agent 12 to add to theconduit 10.

In this embodiment, the masking agent 12 is applied from a masking agentsolution. The masking agent solution is a polymer solution. In theembodiment illustrated and described here, the polymer solutioncomprises approximately 7% w/v PVP (an example of a water-solublepolymer) in water (an example of a solvent). However, it should beunderstood that other polymers, such as glycerol, methyl celluloseand/or PEG could be used. Furthermore, it will be understood that thepolymer solution could comprise between approximately 5% w/v PVP insolution and approximately 30% w/v PVP in solution. Moreover, thepolymer solution could comprise between approximately 5% w/v polymer insolution and approximately 30% w/v polymer in solution. It should beunderstood that the masking agent 12 could comprise approximately 1% w/vof glycerol in solution. Without wishing to be bound by theory, it isthought that an advantage of adding glycerol to the masking agent 12 isthat it mitigates cracking of the masking agent 12 when the maskingagent 12 is added to the conduit 10.

In the embodiment described here, the masking agent 12 comprises PVPwith a molecular weight of approximately 10,000 g/mol. However, itshould be understood that the masking agent 12 could comprise PVP with amolecular weight of between approximately 6,000 g/mol and approximately15,000 g/mol.

While in the embodiment described here the masking agent 12 comprisesPVP, it should be understood that the masking agent 12 could compriseglycerol, methyl cellulose, PEG, PEG, and/or PEG hydrogel.

In the embodiment illustrated and described here, the masking agent 12is biocompatible. However, it should be understood that, in someembodiments the masking agent 12 need not be biocompatible. For example,as described in more detail below, if substantially all of the maskingagent 12 is to be removed from the conduit 10, then the masking agent 12need not be biocompatible. In some embodiments, the masking agent 12need not be removed, and in some embodiments only a part of the maskingagent 12 is removed. In these arrangements, it is advantageous that themasking agent 12 is biocompatible, which allows the conduit 10 to beimplanted in the human or animal body.

In this embodiment, the masking agent 12 is biodegradable. Therefore,any residual masking agent 12 present on the conduit 10 will biodegradewhen the conduit 10 is implanted in the human or animal body. However,the masking agent 12 could be non-biodegradable. In this embodiment,substantially all of the masking agent 12 is removed from the conduit 10prior to implantation, and therefore it is not necessary for the maskingagent 12 to be biodegradable. In some embodiments, it may beadvantageous for the masking agent 12 to be biodegradable.

With reference to FIG. 1 b , the masking agent 12 is applied to theconduit 10 from a polymer solution. However, it will be appreciated thatthe masking agent 12 could be applied to the conduit 10 in other ways.

In this embodiment, the masking agent solution is applied to the conduit10 by immersing the conduit 10 in the masking agent solution forapproximately 1 minute, while agitating the conduit 10. However, itshould be understood that the masking agent solution could be added tothe conduit 10 in other ways, such as by dipping, spray coating, or bybrushing. Furthermore, it should be understood that the masking agent 12could be added to the conduit 10 without agitating the conduit 10.During the step of immersing the conduit 10 in the masking agentsolution, the conduit 10 is moved between the contracted state and theextended state. However, it should be understood that the conduit 10could be immersed in the masking agent solution while the conduit 10 isin the contracted state and/or the extended state.

In this embodiment, when the masking agent solution is added to theconduit 10, solvent is then evaporated from the masking agent solution.Solvent is therefore removed from the masking agent solution, and themasking agent 12 remains on the conduit 10.

In this embodiment, during the addition of the masking agent 12 to theconduit 10, a directed flow of air (an example of a gas) is provided tothe conduit 10. The directed flow of air is directed towards the outersurface 10 b of the wall 10 f of the conduit 10, such that the maskingagent 12 is preferentially formed on the inner surface 10 a of the wall10 f of the conduit 10. It should be understood that while directed airflow is used here, other gases could be used.

In this embodiment, the masking agent 12 is formed, or added,substantially on the inner surface 10 a of the wall 10 f of the conduit10. However, it should be understood that the masking agent 12 could beadded to the outer surface 10 b of the wall 10 f of the conduit 10. Themasking agent 12 is added to the porous section 10 e of the conduit 10,although in other embodiments the masking agent 12 could be added to atleast a part of the porous section 10 e of the conduit 10. In thisembodiment, the masking agent 12 forms a masking agent layersubstantially on the inner surface 10 a of the wall 10 f of the conduit10. However, it should be understood that the masking agent 12 could beadded to other parts of the conduit 10, and that the masking agent 12could form a masking agent layer on other parts of the conduit 10.

In the manufacturing process illustrated and described here, theresidual masking agent 12 on the outer surface 10 b of the wall 10 f ofthe conduit 10 is removed prior to the addition of the sealant 14, inorder to improve the adhesion between the sealant 14 (when applied tothe conduit 10) and the outer surface 10 b of the wall 10 f of theconduit 10. In this embodiment, the residual masking agent 12 on theouter surface 10 b is removed by ablating (an example of a first maskingagent removal step). However, it should be understood that the maskingagent 12 could be removed by applying a solvent, by heating, by etching,by plasma etching, by abrading, and/or by other techniques.

In the embodiment shown in FIG. 1 b , the masking agent 12 is formed onsubstantially all of the inner surface 10 a of the wall 10 f of theconduit 10.

FIG. 1 c shows the conduit 10 after the addition of the masking agent 12and the sealant 14. In the embodiment described here, the sealant 14 isadded to the conduit 10 from a sealant solution. In the embodimentdescribed here, the sealant solution is a polymer solution comprisingroom temperature vulcanising silicone elastomer and xylene. However, itshould be understood that the sealant solution could comprise at leastone of polycarbonate, silicone, silicone elastomer, polyurethane, TPU,one or more thermoplastic elastomers, and/or aliphatic polycarbonate. Itshould also be understood that while the sealant 14 is added to theconduit 10 from a polymer solution comprising xylene, heptane could beused in place of xylene. Furthermore, in some embodiments the sealantsolution may comprise a polar solvent, such as dimethylacetamide (DMAC)or tetrahydrofuran (THF).

When the sealant solution is applied to the conduit 10, solvent isevaporated from the sealant solution, which results in the formation ofthe sealant 14.

While in the embodiment illustrated and described here the sealant 14 isadded to the conduit 10 from a sealant solution, it will be understoodthat the sealant 14 could be added to the conduit 10 in other ways andneed not be added from a sealant solution.

The sealant 14 is added to the porous section 10 e of the conduit 10.Therefore, in this embodiment, the sealant 14 is added to substantiallyall of the conduit 10, as in this embodiment the conduit 10 is entirelyporous 10 e. In other embodiments, the sealant 14 could be added to apart of the porous section 10 e.

The presence of the masking agent 12 prevents the sealant 14 fromadhering, or forming on, the inner surface 10 a of the wall 10 f of theconduit 10. The sealant 14 is applied to the conduit 10 by spraying thesealant 14 onto the outer section 10 b of the conduit 10. However, itshould be understood that other techniques for adding the sealant 14 tothe conduit 10 could be used, such as brushing, wiping, immersing,dipping, vapour depositing, such as chemical vapour depositing,electrostatic spinning, and/or by casting.

In this embodiment, the sealant 14 is applied to the conduit 10, whilethe conduit 10 is in the extended state. However, it should beunderstood that the sealant 14 could be applied to the conduit 10 whilethe conduit 10 is in the contracted state or when the conduit 10 ismoved between the contracted state and the extended state.

In this embodiment, the sealant 14 is added to the conduit 10 while theconduit 10 is rotated about its longitudinal axis at approximately 60rpm. However, it should be understood that the conduit 10 could berotated about its longitudinal axis at up to approximately 2,000 rpm.

In the embodiment described here, the sealant 14 comprises approximately8 mg/cm² of silicone. However, it should be understood that the sealantcould comprise between approximately 4 mg/cm² of silicone andapproximately 19 mg/cm² of silicone.

Spraying and/or brushing the sealant 14 onto the outer surface 10 b ofthe wall 10 f of the conduit 10 is advantageous over some sealantapplication techniques because the sealant 14 is applied substantiallyonly to the outer surface 10 b of the conduit 10 and is notsubstantially applied to the inner surface 10 a of the conduit 10. Inthis arrangement, the masking agent 12, and the addition of the sealant14 to the conduit 10 by way of spraying, and/or brushing, the sealant 14onto the conduit 10, mitigate presence of the sealant 14 on the innersurface 10 a of the wall 10 f of the conduit 10. However, it should beunderstood that other sealant 14 application techniques, such as wipingthe sealant 14 onto the conduit 10, could be used.

In the embodiment illustrated and described here, it is advantageous if,when the sealant 14 is applied to the conduit 10, the masking agent 12is not substantially covered, or blocked, by the sealant 14. The reasonfor this is that, if at least a part of the masking agent 12 is to beremoved from the conduit 10, it is easier to remove the masking agent 12if at least some of the masking agent 12 is exposed. For example, whenremoving at least a part of the masking agent 12 from the conduit 10 byapplying a solvent, it is easier to do so if at least some of themasking agent 12 is exposed. In the embodiments described here, asignificant amount of the masking agent 12 is exposed, and it istherefore relatively straightforward to use a variety of masking agent12 removal techniques.

In this embodiment, the addition of the sealant 14 to the porous section10 e of the conduit 10 forms a sealing layer on the outer surface 10 bof the wall 10 f of the conduit 10. In this embodiment, the sealant 14is biocompatible.

In this embodiment, the sealant 14, when applied to the conduit 10, isconfigured to mitigate against environmental stress cracking.

FIG. 1 d shows a vascular graft 16 (an example of a vascular prosthesis16). In this embodiment, substantially all of the masking agent 12 hasbeen removed from the conduit 10. The leaking of blood (an example of afluid) through the wall 10 f of the conduit 10 is now mitigated due tothe addition of the sealant 14 to the conduit 10. Furthermore, the innersurface 10 a of the wall 10 f of the conduit 10 retains the porous,woven properties of the conduit 10, such that the inner surface 10 a ofthe wall 10 f of the conduit 10 allows for the ingrowth of biologicaltissue and also allows for biological tissue to have good adhesionthereto. The presence of the sealant 14 obviates the flow of bloodthrough the wall 10 f of the conduit 10, although it will be understoodthat blood can flow between the inlet 10 c and the outlet 10 d.

In the embodiment described here and shown in FIG. 1 d , substantiallyall of the masking agent 12 has been removed from the conduit 10 byapplying water to the conduit 10 at a temperature of approximately 95°C. (an example of a second masking agent removal step). In this secondmasking agent removal step, the masking agent 12 has been removed fromthe conduit 10 after the step of adding the sealant 14 to the conduit 10has been carried out. In this process, water (an example of a solvent)has been used to remove substantially all of the masking agent 12 fromthe conduit 10. However, the masking agent 12 need not be removedsubstantially entirely from the conduit 10. Water need not be used asthe solvent, as other solvents could be used to achieve the removal ofthe masking agent 12. It should be understood that the masking agent 12could be removed from the conduit 10 in other ways, such as by etching,plasma etching, ablating, and/or abrading. While the masking agent 12has been substantially removed from the conduit 10 at a temperature ofapproximately 95° C., it should be understood that the masking agent 12could be removed from the conduit 10 at a temperature of betweenapproximately 15° C. and approximately 140° C. In the embodimentdescribed here, the step of removing the masking agent 12 from theconduit 10 is also used to cure the sealant 14 in a more efficientmanner.

In the embodiment depicted in FIG. 1 d , the masking agent removal step,carried out as described above, is carried out for approximately 51minutes while the conduit 10 is agitated. Without wishing to be bound bytheory, agitating the conduit 10 is thought to improve the efficiency ofthe masking agent 12 removal step. Whilst in this embodiment the maskingagent removal step is carried out for approximately 51 minutes, it willbe understood that the masking agent removal step could be carried outfor between approximately 40 minutes and approximately 300 minutes. Itwill also be understood that multiple masking agent removal steps couldbe carried out.

In the embodiment illustrated and described here, the step of removingsubstantially all of the masking agent 12 from the conduit 10 does notresult in the removal of the sealant 14 from the conduit 10.

As described in detail above, the manufacturing process comprises afirst masking agent removal step, designed to improve the adhesion ofthe sealant 14 to the conduit 10, and a second masking agent removalstep, designed primarily to remove the masking agent 12 from the innersurface 10 a of the wall 10 f of the conduit 10. However, it will beunderstood that multiple masking agent removal steps could be carriedout. It should also be understood that for some embodiments of theinvention it may not be necessary to carry out a masking agent removalstep.

In the embodiment illustrated and described here, the vascularprosthesis 16 is reversibly sealable. That is, the sealant 14 could beremoved from the conduit 10 and the sealant 14 could be applied to theconduit 10. For example, this could be necessary in the event of amanufacturing error. Similarly, the masking agent 12 may be added, andremoved from, and subsequently added to the conduit 10. This could benecessary when carrying out more than one masking agent addition step.

In the embodiment illustrated and described here, the vascularprosthesis 16 can be sterilised by way of a gamma sterilisation process.However, it should be understood that the vascular prosthesis 16 couldbe sterilised by way of an electron beam sterilisation process. Anotheroption for sterilising the vascular prosthesis 16 is to carry outethylene oxide sterilisation. It will be appreciated that othersterilisation techniques could be applied to the vascular graft 16,either as an alternative to, or in addition to those described here.

The vascular prosthesis 16 depicted in FIG. 1 d is configured to beimplantable inside the human or animal body and is made fromsubstantially entirely biocompatible materials. The vascular prosthesis16 can be implanted in the human or animal body without being harmful ortoxic to surrounding biological tissue.

The vascular prosthesis 16 illustrated in FIG. 1 d is flexible, whichallows the vascular prosthesis 16 to be manipulated by a medicalpractitioner in a more efficient way. In this embodiment, the additionof the sealant 14 to substantially all of the porous section 10 e of theconduit 10 has converted the unprocessed conduit 10 to a vascularprosthesis 16.

FIGS. 2 a and 2 b show the inner surface 10 a of the wall 10 f of theconduit 10 in more detail. FIGS. 2 a and 2 b show the porous nature ofthe conduit 10. The conduit 10 is a woven structure and, in thisembodiment, is generally a 1/1 twill weave type. As described above, theunprocessed woven conduit 10 will allow blood to leak through the gapsin the fibres of the conduit 10, and it must therefore be sealed priorto implantation in the human or animal body.

The woven nature of the conduit 10 means that it is flexible. Afterapplying the masking agent 12 and the sealing layer 14, the vasculargraft 16 remains flexible, which helps to make the vascular graft 16easier to manipulate and handle by, for example, a medical practitioner.

FIGS. 3 a and 3 b show a detailed view of the inner surface 10 a of thewall 10 f of the conduit 10 after the addition of the masking agent 12.In this embodiment, the masking agent 12 has been added to the conduit10 from a polymer solution (an example of a masking agent solution)comprising approximately 5% w/v PVP in solution. In this embodiment, theconduit 10 has been immersed in the polymer solution. However, asdescribed in more detail above, the masking agent 12 could be added tothe conduit 10 in other ways and the polymer solution could comprisebetween approximately 5% w/v and approximately 30% w/v of polymer insolution. In the embodiment illustrated in FIGS. 3 a and 3 b , theconduit 10 has been immersed in the masking agent solution forapproximately 1 minute. However, it should be appreciated that theconduit 10 could be immersed in the masking agent solution for otherdurations of time.

In the embodiment shown in FIGS. 3 a and 3 b , the masking agent 12substantially blocks the porous section 10 e of the conduit 10. When thesealant 14 is applied to the conduit 10, the masking agent 12 mitigatesthe presence of the sealant 14 on the inner surface 10 a of the wall 10f of the conduit 10. In this embodiment, the masking agent 12 forms anoleophobic layer (an example of a masking layer). Without wishing to bebound by theory, it is thought that the oleophobic properties of themasking layer helps to mitigate the presence of the sealant 14 on theinner surface 10 a of the wall 10 f of the conduit 10. It should beunderstood that in some embodiments the masking agent 12 need not forman oleophobic layer.

FIGS. 4 a and 4 b show the inner surface 10 a of the wall 10 f of theconduit 10 after the sealant 14 has been added to the outer surface 10 bof the wall 10 f of the conduit 10. FIGS. 4 a and 4 b highlight theeffectiveness of the masking agent 12 in mitigating the presence ofsealant 14 on the inner surface 10 a of the wall 10 f of the conduit 10.In this embodiment, the masking agent 12 has been applied to the conduit10 from a masking agent solution comprising approximately 7% w/v of PVPin solution. In the embodiment illustrated in FIGS. 4 a to 5 b , thesealant has been added to the outer surface 10 b of the wall 10 f of theconduit 10 by spray coating a sealant solution onto the outer surface 10b of the wall 10 f of the conduit 10.

FIGS. 5 a and 5 b show the presence of the sealant 14 on the outersurface 10 b of the wall 10 f of the conduit 10 of the embodiment shownin FIGS. 4 a and 4 b . In the embodiment shown in FIGS. 5 a and 5 b ,the sealant solution comprises approximately 15% w/v of silicone inxylene.

FIGS. 4 a and 4 b , and FIGS. 5 a and 5 b , highlight the contrastbetween the inner surface 10 a and the outer surface 10 b of the wall 10f of the conduit 10 after the application of the sealant 14 to theconduit 10. The outer surface 10 b of the conduit 10 is nowsubstantially covered in the sealant 14, whereas the inner surface 10 aof the wall 10 f of the conduit 10 has retained the woven, porousproperties of the conduit 10, because the inner surface 10 a of the wall10 f of the conduit 10 is substantially devoid of the sealant 14. Themasking agent 12 has mitigated the presence of the sealant 14 on theinner surface 10 a of the wall 10 f of the conduit 10. In thisembodiment, the inner surface 10 a of the wall 10 f is configured tofacilitate the growth of biological tissue thereon, and to allow forgood adhesion between ingrowing biological tissue and the inner surface10 a. Presence of the sealant 14 on the inner surface 10 a of the wall10 f of the conduit 10 could have an adverse impact on the ingrowth ofbiological tissue on the inner surface 10 a of the wall 10 f of theconduit 10, and on the adhesion between the biological tissue and theinner surface 10 a of the wall 10 f of the conduit 10.

FIG. 6 a shows a detailed view of the outer surface 10 b of the wall 10f of the conduit 10 after the addition of the sealant 14. In thisembodiment, the sealant 14 is configured to mitigate movement of fluidthrough the wall 10 f of the conduit 10. The wall 10 f of the conduit 10is substantially blood impermeable (i.e., blood cannot pass or leakthrough the wall 10 f at an appreciable rate) after the addition of thesealant 14.

FIG. 6 b shows a detailed view of the inner surface 10 a of the wall 10f of the conduit 10 after the addition of the sealant 14 to the conduit10.

In the embodiment shown in FIGS. 6 a and 6 b , the masking agent 12 hasbeen applied to the conduit 10 from a polymer solution comprisingapproximately 30% w/v PVP in solution, prior to the addition of thesealant 14. As described above, the masking agent 12 can be applied tothe conduit 10 from a polymer solution comprising between approximately5% w/v and approximately 30% w/v of polymer in solution.

One desirable feature for a sealed graft is that it may havesufficiently low levels of permeability to remain predominantly leakproof during the implant procedure. The applicable test method, asprescribed in ISO 7198, Whole Graft Permeability recommends testingusing reverse osmosis (RO) filtered water at a test pressure of 120mmHg. This parameter was based on a de facto standard established by themanufacturers of biologically sealed grafts (gelatin and collagen). Alimit of 0.16 ml/min/cm² may be used to ensure that the graft meets andexceeds sealing capability of aforementioned grafts. Differentapplications, however, may have different permeability requirements, andsuch different permeability requirements are within the scope of thepresent invention.

Further embodiments were prepared according to the manufacturing processillustrated in FIGS. 1 a to 6 b and described above. The furtherembodiments are described in Table 1 below. The manufacturing processused to create the further embodiments listed in Table 1 issubstantially the same as that illustrated and described in relation toFIGS. 1 a to 6 b , with the exception that different masking agents 12and sealants 14 were used.

Commercial textile vascular grafts were used for the tests describedhereinafter. Details for commercial graft samples are described below:

First Commercial Samples of Woven Graft Fabrics:

-   (a) Warp yarn: twisted, texturized, PET, 2 ply / 44 denier per ply    (or bundle) / 27 filaments per ply or bundle.-   (b) Weft yarn: twisted, texturized, PET, 2 ply /, 44 denier per ply    (or bundle) / 27 filaments per ply or bundle.-   (c) Picks per cm, about 40 to 46.

Second Commercial Samples of Woven Graft Fabrics:

-   (a) Warp yarn: 80 Denier, 2 ply / 40 denier per ply (or bundle) / 27    filaments per ply (or bundle), PET, Spun Draw, texturized, 7.5    Twists per inch, Z twist.-   (b) Weft yarn: 2 ply / 40 Denier per ply (or bundle), 2 ply / 40    denier per ply (or bundle) / 27 filaments per ply or bundle, PET,    TXT, S & Z Twist.-   (c) Picks per inch, about 155.

The tests done below in Table 1 were performed on the first commercialsamples of woven graft fabrics.

TABLE 1 Masking Agent Sealant Sealant Coating Method Sealant Coverage(mg/cm²) Leak Rate (ml/min/cm²) Leak Rate ≤0.16 ml/min/cm² PolymerSolvent Polymer Solvent 7% w/v PVP Water 30% w/v Silicone Xylene Brush x1 11.33 0.19 No 7% w/v PVP Water 30% w/v Silicone Xylene Brush x 1 8.300.19 No 4% w/v PVP Water TPU and Silicone THF Brush x 1 2.00 5.79 No 4%w/v PVP Water TPU and Silicone THF Brush x 2 3.70 0.46 No 30% w/v PVPWater 30% w/v Silicone Xylene Brush x 1 5.3 1.78 No 30% w/v PVP Water30% w/v Silicone Xylene Brush x 1 5.2 3.49 No 30% w/v PVP Water 30% w/vSilicone Xylene Brush x 1 7.6 > 12.24 No 25% w/v PVP and 18% w/vGlycerol Water 30% w/v Silicone Xylene Brush x 1 - - No 7% w/v PVP Water30% w/v Silicone Xylene Brush x 1 4.8 0 Yes 7% w/v PVP Water 30% w/vSilicone Xylene Brush x 2 8.9 0 Yes 7% w/v PVP Water 30% w/v SiliconeXylene Brush x 3 8.3 . 0 Yes 7% w/v PVP Water 30% w/v Silicone HeptaneBrush x 1 7.6 0. 69 No 7% w/v PVP Water 30% w/v Silicone Heptane Brush x2 13.8 0.02 Yes 7% w/v PVP Water 30% w/v Silicone Heptane Brush x 3 18.60 Yes 7% w/v PVP Water 30% w/v Silicone Xylene Brush x 1 80 0.09 Yes 7%w/v PVP Water 30% w/v Silicone Xylene Brush x 2 11.5 0.14 Yes 7% w/v PVPWater 30% w/v Silicone Xylene Brush x 2 11.5 0.05 Yes 7% w/v PVP Water30% w/v Silicone Xylene Brush x 3 15.6 0 Yes 7% w/v PVP Water 30% w/vSilicone Xylene Brush x 1 7.1 0.01 Yes 7% w/v PVP Water 30% w/v SiliconeXylene Brush x 2 9.7 0.03 Yes 7% w/v PVP Water 30% w/v Silicone XyleneBrush x2 9.1 0.03 Yes 7% w/v PVP Water 30% w/v Silicone Xylene Brush x 312.6 0.02 Yes 7% w/v PVP Water 30% w/v Silicone Xylene Brush x 1 6.00.22 No 7% w/v PVP Water 30% w/v Silicone Xylene Brush x 2 14.3 0.03 Yes7% w/v PVP Water 30% w/v Silicone Xylene Brush x 2 9.8 0.10 Yes 7% w/vPVP Water 30% w/v Silicone Xylene Brush x 3 13.8 0.06 Yes 12% w/v PVPWater 30% w/v Silicone Xylene Brush x 2 11.0 6.25 No 12% w/v PVP Water30% w/v Silicone Xylene Brush x 2 11.3 1.81 No 7% w/v PVP Water 15% w/vSilicone Xylene Spray x 1 3.5 7.24 No 7% w/v PVP Water 15% w/v SiliconeXylene Spray x 2 5.6 0.07 Yes 7% w/v PVP Water 15% w/v Silicone XyleneSpray x 3 5.3 0.57 No 7% w/v PVP Water 15% w/v Silicone Xylene Spray x 16.7 5.11 No 7% w/v PVP Water 15% w/v Silicone Xylene Spray x 1 8.7 0.01Yes 7% w/v PVP Water 15% w/v Silicone Xylene Spray x 1 6.4 0.02 Yes 7%w/v PVP Water 15% w/v Silicone Xylene Spray x 1 4 8.41 No 7% w/v PVPWater 15% w/v Silicone Xylene Spray x 1 6.3 8.99 No 7% w/v PVP Water 15%w/v Silicone Xylene Spray x 1 3.8 5.05 No 7% w/v PVP Water 15% w/vSilicone Xylene Spray x 1 8.1 1.17 No 7% w/v PVP Water 15% w/v SiliconeXylene Spray x 1 7.9 0.14 Yes 7% w/v PVP Water 15% w/v Silicone XyleneSpray x 1 8.2 5.94 No 7% w/v PVP Water 15% w/v Silicone Xylene Spray x 18.8 1.08 No 7% w/v PVP Water 15% w/v Silicone Xylene Spray x 1 11.4 0.01Yes 7% w/v PVP Water 15% w/v Silicone Xylene Spray x 1 6.8 5.93 No 7%w/v PVP Water 15% w/v Silicone Xylene Spray x 1 7.4 0.16 Yes 7% w/v PVPWater 15% w/v Silicone Xylene Spray x 1 11.9 0 Yes 6% w/v PVP and 1% w/vGlycerol Water 15% w/v Silicone Xylene Spray x 1 7.8 0.04 Yes

A hobby spray gun was used for all spray application tests wheresealants were sprayed onto graft samples. The spray distance from thegraft samples was approximately 50 mm. Grafts were held horizontally onmandrel and rotated in a rotisserie. Spray rates were not measured butwere controlled by a combination of the nozzle traverse rate (estimatedat 2 seconds/cm), graft rotation speed (estimated between one and threerevolutions per second) and overall spray volume rate. Craft bristlebrushes were used for all brush application tests where sealants werebrushed onto graft samples.

As indicated in Table 1, if the wall 10 f has a Leak Rate ≤ 0.16ml/min/cm² then the conduit 10 is considered suitable for implantationand is considered substantially impermeable. In some furtherembodiments, the masking agent 12 comprises glycerol. Without wishing tobe bound by theory, the presence of glycerol in the masking agent 12 isthought to mitigate cracking of the masking agent 12 when applied to theconduit 10.

Masking agents described herein prevent sealants, such as the liquidsilicone elastomer dispersion, from penetrating throughout the thicknessof the graft wall and reaching the lumen or blood contacting surface ofthe graft. Sealants, such as silicone, are believed to adhere to graftfibres on the external surface of the graft through two mechanisms:

-   a. Where graft fibres have had the mask agent ablated or otherwise    free of the masking agents, the liquid silicone elastomer dispersion    adheres to the surface of the graft fibres, such as PET fibres.-   b. Where surface fibres are individually sheathed by the masking    agent, these fibres are encapsulated and a mechanical interlocking    takes place rather than surface adhesion.

Silicone will adhere to the PET fibre surface where there is no maskingagent, but will also encapsulate PET fibres which are sheathed inmasking agent.

The masking agent is believed to act like a slurry when applied to atextile and can flow and cover gaps between the yarn bundles and alsoseep between the yarn fibers. It acts as a viscous mixture movingthrough the fabric and settling and collecting at areas of low energy.Rather than attaching to individual fibers it continues to move and pooluntil a masking agent drying process initiates and through theevaporation of its solvent, such as water, the masking agent thensolidifies wherever it has gathered.

The elastomeric sealant (e.g., silicone) may not adequately attach tothe textile surface where excessive concentrations of masking agent arepresent. If the masking agent is too viscous and has fully encapsulatedan area of fabric and then dried, there may be no exposed yarn filamentsfor the silicone to mechanically encapsulate and lock onto. Without thismechanical encapsulation of the yarn by the silicone, then the adhesionmay be poor and possibly non-existent once the masking agent is removed.

While the masking agent may appear to thinly coat the individualfilaments as it moves or washes through the textile, the concentrationsremaining in these washed through areas after drying are not sufficientto prevent subsequent encapsulation and adhesion of the siliconeadhesive to the yarn bundles.

Any synthetic hydrophilic polymer and any biological hydrophilicpolymer, e.g., gelatin, partially hydrolysed collagen, dextran,hyaluronic acid, alginates and starches (e.g., hydroxyethyl starch) andchitosan may be used as masking agents. Pluronic F127 PEG, which issoluble in cold water but insoluble in warm water, may also be used as amasking agent. Desirably, masking agents derived from animal productsmay are removed prior to vascular applications. As such, the maskingagents, including animal derived masking agents, if any, are removedfrom the final product, such grafts may suitable be used in vascularapplications. Furthermore, as the masking agents are removed from thetextile graft prior to any applications with a patient, includingvascular applications, the masking agents need not be biocompatible.

Desirably, the masking agent is highly soluble in water. It can be anypolymer which can swell in a liquid which has a Hildebrand SolubilityParameter (Delta SI units) of 24 or higher.

Masking agents useful with the present invention may have molecularweights from about 400 or 1,000 to about 1,000,000. Desirably, themolecular weight may vary from about 3,000 to about 30,000, and moredesirably from about 6,000 to about 15,000

One useful sealant may be a dispersion of silicone in a nonpolar‘solvent’ or carrier medium. Useful cross linking is through acetoxy‘room temp vulcanisation’ chemistry but two part platinum cure chemistrycould also be used as well as ultraviolet (UV) curing.

For samples employing a polymer supplied as a dispersion, for exampleNuSil MED 6605 and Med 6606, discrete amounts of polymer dispersion weredecanted by weight into individual pots for either direct coating ontothe graft or further addition of solvent, by weight.

All silicone dispersions used were acetoxy curing. Curing schedules arerecommended at 72 hours, however due to the extremely thin crosssection/ large surface area of the graft, full cures have been observedapparent within 24 hours. Subsequent washing of the device in water mayspeed up the curing and ensure full cross linking. These times are,however, non-limiting, and other cure times and conditions may suitablybe used.

The preferred polymers for coating, in order to achieve a soft andflexible graft with handling characteristics similar to that of agelatin sealed graft, are those with very low Shore hardness values. Thepreferred silicone elastomers, MED 6605 and MED 6605 have Durometer TypeA values of 25 and 20 respectively. Both of these grades can providegrafts with suitable flexibility and handling characteristics, when thincoatings are applied. As multiple coatings are applied, stiffness mayincrease and flexibility may reduce.

Harder grades can be used as an alternative to thicker coatings in orderto create stiffer grafts if required.

Alternative coatings, such as TPU-Silicones (Advansource Chronosil 75Aor Aor-Tech Elast-Eon E5-130) can be used however, these have DurometerHardness of 75A and 77A respectively, therefore may create grafts whichmay be stiffer, if desired, than current gelatin sealed grafts. Suchstiffer grafts may have some benefits for specific applications,however, may not meet expectations for conventional surgeon handling.

Additional useful sealant materials include, but are not limited to:

-   (a) Applied Silicone Corporation, PN 40021, Implant grade high    strength RTV Silicone Elastomer Dispersion in Xylene. This material    is suitable for use in fabricating high strength, elastic membranes    of any shape and thickness using processes such as dipping, casting,    spraying or brushing. After evaporating the solvent, the silicone is    room temperature vulcanized (RTV) by exposure to ambient air. The    key features of this material are high strength, low durometer,    (Shore A 24) and is supported by ISO 10993 testing and compendium to    support regulatory submissions.-   (b) AdvanSource Biomaterials Corporation, ChronoFlex AR,    polycarbonate based thermoplastic urethanes. These materials may be    used for moulding, casting and dip-coating and are fully synthesized    in liquid providing high strength & elongation while maintaining the    inherent polycarbonate advantage of long-term permanent durability    and resistance to environmental stress cracking (ESC). Additionally,    they may be electrospun or used in water emulsion processes.    Examples of specific useful materials include, but are not limited    to, ChronoFlex C80A 5% and ChronoFlex AR 23%.

Suitable sealants are low durometer elastomers (desirably less than orequal to about 40A durometer or shore hardness 40A, more desirably lessthan or equal to about 30A durometer or shore hardness 30A, even moredesirably less than or equal to about 20A durometer or shore harness20A) and have good biostability.

One parameter which may be considered in the choice of sealant is thestiffness or elastic modulus. Usually with elastomers the modulus is notlinear thus at each elongation the stress (or force) is measured. Amaterial with lower stress @ % strain will provide less resistance toextension and will therefore feel more flexible and closer to matchingthe handling of a gelatin sealed graft.

Preferred materials are low stress silicone rubbers, such as NuSil MED6605 and MED 6606, with Stress @ Strain values < 180 @ 200%.

Useful Polyurethane and Silicone-polyurethane grades, include, but arenot limited to:

TABLE 2 Material Manufacturer Grade Stress (psi) at % elongationSilicone Rubber NuSil MED 6606 50 @ 100% Silicone Rubber NuSil MED 6605160 @ 300% Silicone Rubber Applied Silicone Dispersion PN 40021 170 @300% TPU-Silicone Advansource ChronoSil adjusted 570 @ 200% TPU-siliconeBiomerics Quadrasil Elast-EON E5-130 725 @ 200% TPU-aliphaticpolycarbonate Advansource Chronoflex AL 75A 800 @ 200% TPU-10% siliconeAdvansource ChronoSil 75A 10% Si 834 @ 200%

The present invention is not limited to the use of silicone as thepolymeric sealant. Other useful coating materials for both medical andnon-medical textiles may include, for example, polytetrafluoroethylene,polyethylene, poly(hydroxyethly methacrylate), poly(vinyl alcohol),polycaprolactone, poly(D, L-lactic acid), poly(L-lactic acid),poly(lactide-co-glycolide), poly(hydroxybutyrate),poly(hydroxybutyrate-co-valerate), polydioxanone, polyorthoester,polyanhydride, poly(glycolic acid), poly(glycolic acid-cotrimethylenecarbonate), polyphosphoester, polyphosphoester urethane, poly(aminoacids), cyanoacrylates, poly(trimethylene carbonate),poly(iminocarbonate), copoly(ether-esters), polyalkylene oxalates,polyphosphazenes, polyiminocarbonates, aliphatic polycarbonate,polyethylene oxide, polyethylene gylcol, poly(propylene oxide),polyacrylamide, polyacrylic acid (30-60% solution), polymethacrylicacid, poly(N-vinyl-2-pyrollidone), polyurethane, poly(aminoacid),cellulosic polymer (e.g. sodium carboxymethyl cellulose, hydroxyethylcelluslose), collagen, carrageenan, alginate, starch, dextrin, gelatin,poly(lactide), poly(glycolide), polydioxanone, polycaprolactone,polyhydroxybutyrate, poly(phospazazene), poly(phosphate ester),poly(lactide-co-glycolide), poly(glycolide-co-trimethylene carbonate),poly(glycolide-co-caprolactone), polyanhydride, polyamide, polyesters,polyether, polyketone, polyether elastomer, parylene, polyether amideelastomers, polyacrylate-based elastomer, polyethylene, polypropylene,and/or and derivatives thereof. Other useful coating materials, inparticular for but not limited to non-medical textiles, may includenatural rubbers, natural gums, acrylic polymers, polybutadienes,styrene-butadiene copolymers or rubbers, butadiene-acrylonitrilecopolymers, polyisobutylenes, isoprene-isobutylene copolymers,polysulfide rubbers, chloroprene rubbers (neoprene), chlorosulfonatedpolyethylene, fluorinated polymers, vinyl resins, and the like. Further,coating materials may include metallic materials and powdered materials.

FIG. 7 depicts a further embodiment of the conduit 10. As best shown inFIG. 7 , the conduit 10 comprises a number of crimps 10 g. In thisembodiment, a support member 18 is added to the outer surface 10 b, ofthe wall 10 f of the conduit 10. In particular, the support member 18 isadded by multiple stages of sealant application. For example, thesealant may be added to the outer surface of the conduit 10 as describedabove, then the support member 18 may be disposed over the sealed graft,followed by applying another stage of sealant application, which afterdrying and/or curing will aid in the securement of the support member 18to the conduit 10. However, it should be understood that the supportmember 18 could be added to the conduit 10 in other ways. The step ofadding the support member 18 to the outer surface 10 b of the wall 10 fof the conduit 10 is carried out prior to the step of adding the sealant14 to the conduit 10. The sealant 14 is configured to attach the supportmember 18 to the conduit 10. In this embodiment, the support member 18is added to the conduit 10 and the sealant 14 is then added to theconduit 10 in order to seal the conduit 10, and to attach the supportmember 18 to the conduit 10. Moreover, it should be understood that itis within the scope of the present invention to have multipleapplications of masking agent and/or sealant either after or prior todrying and/or curing the prior application.

The support member 18 is a flexible, polymer wire, which in thisembodiment is wrapped around the outer surface 10 b of the wall 10 f ofthe conduit 10 and is arranged to nest between the crimps 10 g of theconduit 10. One of the advantages of adding the support member 18 to theconduit 10, as illustrated and described here, is that the conduit 10 ismade more robust while retaining much of its flexible characteristics.As stated above, the conduit 10 is able to be manipulated by a medicalpractitioner in a more efficient way because the conduit 10 is flexible.

In the embodiment illustrated in FIG. 7 , the support member 18 is madefrom polyethylene terephthalate (PET). However, it is understood thatthe support member 18 could comprise at least one of: a polymermaterial, a metal material, a shape memory alloy, and a superelasticalloy. In some embodiments, the support member 18 could comprise atleast one of: polyethylene terephthalate, polytetrafluoroethylene,polyurethane, polycarbonate, silicone, stainless steel, titanium,nickel, and nickel titanium (Nitinol).

FIG. 8 shows an alternative embodiment of a conduit 10 manufacturedaccording to the process illustrated in FIGS. 1 a to 1 d . The conduit10 depicted in FIG. 8 has been manufactured in the same way as thatdepicted in FIG. 1 d , with the following differences. The conduit 10has three sections 10 h, 10 i, 10 j. Sealant 14 a, 14 b and 14 c hasbeen selectively added to the sections 10 h, 10 i, 10 j, such that eachsection 10 h, 10 i, 10 j, has a different amount of sealant 14 a, 14 b,14 c, present thereon. In this embodiment, each of the sections 10 h, 10i, 10 j have a substantially different degree of flexibility. The firstsection 10 h has a higher degree of flexibility than the second section10 i. Similarly, the second section 10 i has a higher degree offlexibility than the third section 10 j. As shown in FIG. 8 , the crimps10 g of the first section 10 h are more visible than in the secondsection 10 i and third section 10 j, because the second and thirdsections 10 i, 10 j, have a higher amount of sealant added thereto,which causes the crimps 10 g in these sections 10 i, 10 j, to be lesspronounced. In applications where a further prosthesis is connected toan end of the vascular prosthesis 16, the end of the third section 10 jis more suited for connection to the further prosthesis.

An example of how the vascular graft 16 may be used will now beprovided.

The vascular graft 16 described in FIGS. 1 a to 6 b , which may bethought of as a sealed, processed conduit 10, is capable of beingimplanted in the human or animal body over the long term. This isbecause the vascular graft 16 is biocompatible, that is it will notillicit a foreign body response in the human or animal body, and it isnot toxic to surrounding biological tissue.

The masking agent 12 is configured to biodegrade in the body. Therefore,any residual masking agent 12 present on the conduit 10 will biodegradein the body. However, as described in more detail above, the maskingagent 12 need not be biodegradable, as in some embodiments the maskingagent 12 will be removed substantially entirely from the conduit 10. Inother embodiments, the masking agent 12 need not be removed from theconduit 10.

The vascular graft 16 can be used to bypass a region, or a section of ablood vessel. For example, if a medical practitioner identifies ablocked, a diseased region or partially blocked region of a bloodvessel, they may decide to bypass that region by using the vasculargraft 16. In this example, the inlet 10 c of the vascular graft 16 maybe attached to one point of the blood vessel, and the outlet 10 d of thevascular graft 16 may be attached to another point of the blood vessel.In another example, the blood vessel could be diseased, or have beensevered or bisected in order to connect the vascular graft 16 to twoends of the severed blood vessel. Because the vascular graft 16 issealed, blood may flow through the vascular graft 16 in order to bypassthe blocked, diseased, or partially blocked region of the blood vessel,and the leaking of blood through the walls 10 f of the conduit 10 ismitigated by the presence of the sealant 14.

Once the vascular graft 16 is in place, biological tissue will grow intothe inner section 10 a of the vascular graft 16 in order to form apseudointima. Over time, the psuedointima will form, adhering to theinner section 10 a of the vascular graft 16. During this time, thevascular graft 16 prevents leakage of blood through the wall 10 f andacts as a scaffold for the ingrowing biological tissue.

The vascular graft 16 may also be used to connect a further prosthesis,such as a heart assist device, a biological heart valve or a syntheticheart valve, to a blood vessel. For example, the inlet 10 c of thevascular graft 16 may be connected to an outlet of a synthetic heartvalve, and the outlet 10 d of the vascular graft 16 may be connected toan end of a blood vessel. The advantage of this use of the vasculargraft 16 is that a heart assist component can be used with a widevariety of shapes and sizes of blood vessels, as the vascular graft 16can be provided in a range of sizes. The medical practitioner is thenable to select which particular vascular graft 16 will interface wellwith the synthetic heart valve and the blood vessel. This avoids theneed for a range of different configurations of heart assist device tobe used, as a standard part can be used and customised by addingdifferent types and sizes of vascular graft 16. It will be appreciatedthat, depending on the nature of the heart assist device, multiplevascular grafts 16 could be used with the heart assist device.

While the embodiments illustrated and described here show a cylindricalconduit 10 with an inlet 10 c and an outlet 10 d, other shapes ofconduit 10 could be used. For example, a Y shaped, T-shaped, or amulti-channel conduit 10 could be used.

FIG. 9 a is a perspective view of a perforated mandrel 20 useful withthe systems and/or kits of the present invention for processing textilesubstrates in accordance with the present invention. As depicted inFIGS. 9 a and 9 b , the mandrel 20 may be a hollow mandrel having anopen lumen 24. One or both ends 26 of the mandrel 20 may be open ends.Alternatively, one or both ends 26 of the mandrel 20 may be closed ends(not shown). As depicted in FIGS. 9 a and 9 c , perforations or holes 23may be disposed within the tubular wall of the mandrel 20.

The mandrel 20 may be used for a variety of purposes. For example, themandrel 20 could be used to deliver the masking agent or thewater-soluble material to a tubular textile, such as a graft. In such ause, a tubular textile (not shown) may be disposed over the outersurface 22 of the mandrel 20. The masking agent or the water-solublematerial may be delivered into the open lumen 24 of the mandrel 20, forexample into the open lumen 24 via an open end 25. The opposed end maybe closed or open, such as in the case of a circulating system for thefluid masking agent or water-soluble material. The fluid masking agentor water-soluble material would flow through the perforations or holes23 and onto and into the graft (not shown) disposed over the mandrel 20.

The mandrel 20 may have a controlled amount of fluid masking agent orwater-soluble material within the lumen 24 to control the amount offluid masking agent or water-soluble material exposed to the graft (notshown). The fluid masking agent or water-soluble material containedwithin the mandrel 20 may be forced onto the graft through the use of apressure differential (higher pressure within the lumen 24 than outsidethe lumen 24) or through rotational forces when the mandrel 20 isdisposed on or within a rotating or spinning device.

A mandrel not having the perforations 20 (not shown) may be used todispose a layer of fluid masking agent or water-soluble material overthe outer surface of the mandrel. The masking layer may be viscousenough or partially cured to remain on the mandrel until a graft isdisposed over the mandrel. The masking layer may then be releasablydisposed over the inner surface of the graft.

The mandrel 20 may also be used for control of fluid migration. Forexample, the pressure within the lumen 24 may be lower than the pressureoutside of the lumen 24. Such a negative pressure or vacuum may be usedto migrate the masking agent or water-soluble material away from theouter surface of a graft (not shown).

The mandrel 20 may also be used for drying the fluid masking agent orwater-soluble material. A warm gas, such as air, may be introduced intothe lumen 24, flow through the perforations or holes 23, and dry thefluid masking agent or water-soluble material. Alternatively, a heatsource may be disposed outside of the mandrel 20, and the flow of heat,such as heated air, may be controlled through the application of anegative pressure at the lumen 24.

A mandrel, either the same or different, may be used throughoutdifferent applications and techniques described herein, such as, but notlimited to, masking agent application and/or dispersion, masking agentdrying, sealant application and/or dispersion, sealant drying and/orcuring, textile washing, and the like. A tubular textile may besubstantially disposed over a mandrel or only a portion of the tubulartextile may be disposed over a mandrel. For example, one end of atubular textile may be supported by a mandrel and the other end of thetubular textile may be supported by a different mandrel, and the like.

The substantially water-insoluble sealant may also be applied to thegraft while the graft is on a solid or non-perforated mandrel or on aperforated mandrel 20. The substantially water-insoluble sealant may beapplied to the graft by any suitable means, such as by brushing,spraying, roller coating, spinning the substantially water-insolublesealant thereon.

Furthermore, if desired the substantially water-insoluble sealant may becured with the graft disposed over a mandrel.

Further, other materials, such as colorants, therapeutic agents, dyes,fluorescent indicators, and the like maybe applied to the graft.

Therapeutic agents may include, but are not limited to:anti-thrombogenic agents (such as heparin, heparin derivatives,urokinase, and PPack (dextrophenylalanine proline argininechloromethylketone); anti-proliferative agents (such as enoxaprin,angiopeptin, or monoclonal antibodies capable of blocking smooth musclecell proliferation, hirudin, and acetylsalicylic acid);anti-inflammatory agents (such as dexamethasone, prednisolone,corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine);antineoplastic/antiproliferative/anti-miotic agents (such as paclitaxel,5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones,endostatin, angiostatin and thymidine kinase inhibitors); anestheticagents (such as lidocaine, bupivacaine, and ropivacaine);anti-coagulants (such as D-Phe-Pro-Arg chloromethyl keton, an RGDpeptide-containing compound, heparin, antithrombin compounds, plateletreceptor antagonists, anti-thrombin antibodies, anti-platelet receptorantibodies, aspirin, prostaglandin inhibitors, platelet inhibitors andtick antiplatelet peptides); vascular cell growth promoters (such asgrowth factor inhibitors, growth factor receptor antagonists,transcriptional activators, and translational promotors); vascular cellgrowth inhibitors (such as growth factor inhibitors, growth factorreceptor antagonists, transcriptional repressors, translationalrepressors, replication inhibitors, inhibitory antibodies, antibodiesdirected against growth factors, bifunctional molecules consisting of agrowth factor and a cytotoxin, bifunctional molecules consisting of anantibody and a cytotoxin); cholesterol-lowering agents; vasodilatingagents; agents which interfere with endogenous or vascoactivemechanisms; and combinations thereof.

Masking Agent Drying and Uniformity Tests

Tests were performed to determine how long it took for a standard wovengraft immersed in PVP to dry at different concentrations, and if PVPdried in a homogeneous fashion throughout the textile. A series of testsat different concentrations of PVP were done to determine if theconcentration made a difference on the drying nature of the substance.

The tests used 15%, 10% & 5% PVP solution profiles. First, a 15%solution of PVP was made with 15 g of PVP and 100 mL of water. This wasagitated until PVP was fully dissolved into solution. Graft samples wereprepared by cutting approximately 50 mm of a commercial tubular graft.The graft samples were, if necessary, dried and were weighed. Graftsamples were then soaked in the 15% PVP solution. The wet grafts wereweighed to provide initial weights. The samples were placed verticallynear a running fan. The graft samples were weighed at 5-minute intervalsuntil there was a constant weight being displayed. The graft sampleswere cut into 4 labelled pieces. Each quarter piece was weighed. Thequarter pieces were then washed, dried, re-weighed when fully dry. Thelengths of the dry-washed graft were measured.

Next, 50 mL of water was added to the 15% PVP solution in order to makea 10% PVP solution. The above textile processing steps were repeated forthe 10% PVP solution

Next 150 mL of water was added to the 10% PVP solution to make a 5% PVPsolution. The above textile processing steps were repeated for the 5%PVP solution.

Results: 15% PVP Profile

TABLE 3 Time (min) Weight (g) Dry 1.709 0 4.817 5 4.229 10 3.81 15 3.39920 3.056 25 2.775 30 2.543 35 2.36 40 2.235 45 2.152 50 2.122 55 2.11760 2.113 65 2.113 Length measured Length (mm) Initial 51 Final 52Quarter With PVP Without PVP wt% PVP in piece 1 0.507 0.418 17.6 2 0.5190.421 18.9 3 0.569 0.461 19.0 4 0.516 0.427 17.2 Total 2.111 1.727 18.2Total expected 2.113 1.709

Table 3 showed that the 15% PVP coated graft took over an hour to dryfully in ambient air, it also showed that there was a slight increase inthe length of the graft after being coated, washed and dried. Afterdrying, the samples averaged 18.2 weight percent PVP. Further, thedistribution of PVP among the samples was substantially consistent.Graft samples or pieces 2 and 3 had slightly higher PVP levels. Thesepieces had a seam of the graft on them, so it appeared that the seam wasprobably absorbing more PVP. Thus, about 15 to about 21 weight percentPVP was deposited onto the graft when immersed in the 15% PVP solution.

Results: 10% PVP Profile

TABLE 4 Time (min) Weight (g) Dry 1.699 0 4.891 5 4.292 10 3.881 153.491 20 3.159 25 2.849 30 2.580 35 2.124 40 2.040 45 2.000 50 1.994 551.994 Length measured Length (mm) Initial 48 Final 51 Quarter With PVPWithout PVP wt% PVP in piece 1 0.543 0.469 13.6 2 0.598 0.51 14.7 30.394 0.334 15.2 4 0.459 0.394 14.2 Total 1.994 1.707 14.4 Totalexpected 1.994 1.699

Table 4 showed that the 10% PVP covered graft took just under an hour todry completely, and that the 10% PVP solution covering, washing anddrying had also caused a slight increase in the length of the graft. Theslightly higher weight % of PVP in pieces 2 and 3 also suggested thatthe seam of the graft absorbed more of the PVP than the rest of thegraft. After drying, the samples averaged 14.4 weight percent PVP. Thus,about 10 to about 18 weight percent PVP was deposited onto the graftwhen immersed in the 10% PVP solution.

Results: 5% PVP Profile

TABLE 5 Time (min) Weight (g) Dry 1.514 0 3.197 5 2.735 10 2.385 152.070 20 1.820 25 1.650 30 1.590 35 1.588 40 1.588 Length measuredLength (mm) Initial 47 Final 47 Quarter With PVP Without PVP wt% PVP inpiece 1 0.357 0.348 2.5 2 0.423 0.406 4.0 3 0.432 0.412 4.6 4 0.3710.354 4.6 Total 1.583 1.52 4.0 Total expected 1.588 1.514

Table 5 showed that the 5% PVP covered graft took the least time to drycompletely, and that its length did not seem to alter after coating,washing and drying, the PVP did to a minor degree to ‘sink’ to thebottom of this graft. Thus, about 2 to about 8 weight percent PVP wasdeposited onto the graft when immersed in the 5% PVP solution.

Conclusions

The 15% PVP covered graft took the most time to dry by approximately 25minutes. In terms of drying evenly anyone of these concentrations wasacceptable.

Various drying techniques are suitable for use with the presentinvention. For example, textile grafts and/or textile substrates may bedried at room temperature to remove the solvent(s) from the depositedmasking agent solution and/or from the sealant solution. Forced air,such as use of a fan or fans or other sources of air movement and/orsources of pressurized air, may be used to facilitate drying. The forcedair, if any, may be applied at any suitable angle or combination ofangles. The air may or may not flow into the interior lumen of thegraft. For example, forced air may be directed towards outer surface ofa tubular graft, either perpendicularly, substantially perpendicularly,at an acute angle, and/or at an obtuse angle. Moreover, forced air maybe directed towards the interior lumen of the tubular graft, such astowards one open end of the tubular graft, or even from within theinterior lumen of the tubular graft. The direction of air flow and theamount of extend of the air flow may be varied to control drying timesand even to control resultant physical properties of the graft. Forcedair flow may also be useful in aiding migration of the masking agenttowards the interior portions of the graft and away from exteriorportions of the graft. In other words the masking agent desirablyretracts when drying. This would aid in the securement of the sealantmaterial at the exterior portions of the textile graft while also aidingin the blocking of sealant migration towards the interior portions ofthe graft. The present invention, however, is not limited to the use ofair as a drying medium, and other suitable media, including gaseousmedia, may be used. Further, the present invention is not limited toroom temperature drying, and elevated drying temperatures above roomtemperature may suitably be used.

Moreover, a fluid, such as water, including heated water, may be usedwith the present invention as described below. The use of heated wateraids in the removal of the water-soluble masking agent from the textileproduct. Further, the use of heated water may also aid in curing of thesealant or sealing agent.

Furthermore, drying and/or curing the sealant material may also becontrolled using forced air or other medium, ambient forced air or othermedium, heated forced air or other medium, non-forced ambient air orother medium, non-forced heated air or other medium, and the like. Notonly may curing times of the sealant material be controlled, but also,to some extent, the properties of the sealant layer may be controlled.The sealant material may be selected, dried or cured, and or selectivelydeposited, such that the sealant material, as is cures, shrinks aboutthe textile substrate, e.g., the outer surface of the textile graft.

Masking Agent Removal Tests

Different washing methods for the grafts were performed to determinewhich method would extract the highest levels of PVP and if the chosenmethod has any effect on the length and crimp of the graft.

Two wash processes were considered, an Ultrawave ultrasonic bath and adomestic washing machine.

Procedures Part 1: No Sealant Coating

This trial was first done on 6 grafts that were not coated with siliconein order to establish if 100% of the PVP could be removed with thechosen washing methods.

Grafts were prepared by cutting approximately 6 × 60 mm lengths ofcommercial woven grafts. All 6 grafts were measured, weighed, andlabelled with notches cut into the side. A 15% PVP solution was madewith 15 g of PVP and 100 mL of water. All 6 samples were submerged inthe 15% PVP in solution. All 6 samples were dried vertically near arunning fan. All dried samples were weighed.

An ultrasonic bath was set to 40° C. Samples 1, 2, and 3 were submergedinto the ultrasonic bath. Samples 1-3 were left in the ultrasonic bathfor 15 minutes. These samples were removed from the ultrasonic bath andwere dried vertically near a fan. The dried 1-3 samples were weighed andtheir lengths were measured and recorded.

Samples 4, 5, and 6 were placed in a washing bag and then into a washingmachine. The washing machine was set to a 40° C., 800 RPM, 51 minutewool wash setting. Samples 4-6 were removed from the washing machine andwere allowed to dry. Samples 4-6 were weighed and their lengths wererecorded.

Part 2: Silicone in Heptane Sprayed Sealant Coating

Samples 1-3 were re-washed, dried, measured and weighed. Samples 1-3were then submerged in the 15% PVP solution. All 6 samples were driedvertically near a running fan. The dried samples were weighed.

All 6 samples were stretched out and sprayed with silicone in heptanecoating. The 6 samples were then allowed to return to their relaxedstates under a fume hood and were allowed to dry. An ultrasonic waterbath was set to 40° C. Once dry, samples 1-3 were submerged in theultrasonic bath for 15 minutes. These samples were removed from the bathand were dried vertically near a fan. The dried samples 1-3 wereweighed, and their lengths were measured and recorded.

Once dry, samples 4-6 were placed in a washing bag and then into awashing machine. The washing machine was set to a 40 degree Celsius, 800RPM, 51 minute wool wash setting. The samples were removed from thewashing machine and were allowed to dry. Once dry, the samples 4-6 wereweighed, and their lengths were measured and recorded.

Results

TABLE 6 No Sealant Coating Ultrasonic Bath at 40 Degrees Washing MachineWool Setting Measurement Sample 1 Sample 2 Sample 3 Sample 4 Sample 5Sample 6 Initial Weight (g) 2.747 3.177 2.456 2.641 2.772 2.846 DriedPVP weight (g) 3.508 4.048 3.179 3.445 3.568 3.658 Washed Weight (g)2.779 3.212 2.467 2.641 2.772 2.847 PVP left (g) 0.032 0.035 0.011 0.0000.000 0.001 Initial Length (mm) 62.5 61 57 57 56 63.5 Final Length (mm)62.5 62 57 57 56 63.5

The majority of the samples that were put in the washing machine werecleared of PVP while the samples that were put in the ultrasonic bathall still had some minor PVP on them after washing.

TABLE 7 Silicone in Heptane Sprayed Sealant Coating Ultrasonic Bath at40 Degrees Washing Machine Wool Setting Measurement Sample 1 Sample 2Sample 3 Sample 4 Sample 5 Sample 6 Initial Weight (g) 2.747 3.177 2.4562.641 2.772 2.847 Dried PVP weight (g) 3.510 3.911 3.123 3.389 3.5383.57 Dried PVP + Coating weight (g) 3.737 4.08 3.323 3.583 3.843 3.825Washed Weight (g) 2.779 3.212 2.467 2.641 2.772 2.847 Silicone applied(g) 0.227 0.169 0.200 0.194 0.305 0.255 PVP + silicone left on graft (g)0.252 0.186 0.214 0.206 0.312 0.266 PVP left (g) 0.025 0.017 0.014 0.0120.007 0.011 Initial Length (mm) 62.5 61 57 57 56 63.5 Length aftercoating (mm) 81 79 73 79 79 79 Final Length (mm) 70 66 62 61 64 65 Ratioof PVP Applied to Silicone Applied, wt./wt. 3.4 4.3 3.3 3.9 2.5 2.8Ratio of Silicone Applied to PVP Applied, wt./wt. 0.29 0.23 0.30 0.260.40 0.36 Percent PVP Removed, wt. % 96.7 97.7 97.9 98.4 99.1 98.5

Although there was some PVP left on the grafts that went in the washingmachine, there is significantly less PVP left on them as opposed to thegrafts washed in the ultrasonic bath. In all cases, greater than about90 weight percent of the PVP was removed. Indeed, in all cases greaterthan about 95 weight percent of the PVP was removed.

In Table 7, the weight ratio of PVP to silicone applied varied fromabout 2.5:1.0 to about 4.3:1.0. Conversely, the weight ratio of siliconeto PVP applied varied from about 0.40:1.0 to about 0.23:1.0.

Further, ratios are described in Table 11 below.

The ratios described in Tables 7 and 11 are non-limiting.

The weight ratio of PVP (or other masking agents) to silicone (or othersealant agents) may vary from about 10:1 wt. PVP (or other maskingagents) / wt. silicone (or other sealant agents) to about 0.01:1 wt. PVP(or other masking agents) / wt. silicone (or other sealant agents),desirably from about 1:1 wt. PVP (or other masking agents) / wt.silicone (or other sealant agents) to about 0.05:1 wt. PVP (or othermasking agents) / wt. silicone (or other sealant agents), more desirablyfrom about 0.5:1 wt. PVP (or other masking agents) / wt. silicone (orother sealant agents) to about 0.1:1 wt. PVP / wt. silicone.

Conversely, the weight ratio of silicone (or other sealant agents) toPVP (or other masking agents) may vary from about 0.1:1.0 wt. silicone(or other sealant agents) / wt. PVP (or other masking agents) to about100:1 wt. silicone (or other sealant agents) / wt. PVP (or other maskingagents, desirably from about 1:1 wt. silicone (or other sealant agents)/ wt. PVP (or other masking agents to about 20:1 wt. silicone (or othersealant agents) / wt. PVP (or other masking agents, more desirably fromabout 2:1 wt. silicone (or other sealant agents) / wt. PVP (or othermasking agents to about 10:1 wt. silicone (or other sealant agents) /wt. PVP (or other masking agents.

Mask and Dye Tests Materials

Fabric – Diameter 22 mm, flat tube twill weave and Diameter 10 mm.Crimped twill weave.

Silicone – NuSil Med16-6606 (Temporary implant grade).

Solvent – n-Heptane, 50:50 with silicone dispersion.

Dye – Easy Composites Royal blue pigment for RTV silicone, mixed toapprox. 10% of silicone solid content.

Sample Description

For Flat 22 mm fabric samples, the following masking agent formulationswere used:

-   #71 A – Bare Fabric-   #71 B – 6% PVP-   #71 C – 6% PVP + 1.5% Glycerol (by volume of Mask solution)-   #71 D – 6% PVP + 1.5% Glycerol + 4% PVP (Total 10% PVP)

The #71B-D flat fabric samples were immersed into the PVP solution andthen removed. All #71 samples were mounted on suspended mandrels (Postmasking, Pre-coating).

For Crimped Diameter 10 mm fabric samples, the following masking agentformulations were used:

-   #70 A – Bare Fabric-   #70 B – 6% PVP-   #70 C – 6% PVP + 1.5% Glycerol (by volume of Mask solution)-   #70 D – 6% PVP + 1.5% Glycerol + 4% PVP (Total 10% PVP)

The #70B-D crimped fabric samples were immersed into the PVP solutionand then removed. All #70 samples were mounted on suspended mandrels(Post masking, Pre-coating).

Masking Agent Preparation

Masking agents were prepared using the same method as described above,with the additional steps to add glycerol for samples B and C (both #70and #71) and then additional PVP for samples D (both #70 and #71).

Measured the target weight of PVP into plastic beaker on scale balance.A 100 ml masking agent solution was prepared therefore target mass of 4g PVP required (4% concentration). Measured the target volume ofde-ionised water into a 100 ml plastic measuring cylinder. A 100 ml Masksolution to be prepared therefore target volume of 96 ml required. Addedde-ionised water into the PVP in plastic beaker. Placed magnetic stirrerin the water and place the beaker on the magnetic stirrer. Turned themagnetic stirrer on at a speed of 350-450 RPM, ensuring the stirrer iscentred in the beaker. The stirring was done at room temperature.Stirring was continued until there was no visible PVP solute, or for aminimum of at least 2 minutes. After stirring the masking agent solutionwas removed from stirrer and used for graft preparation, samples B.

Additional steps were used for samples C, i.e. added glycerol. Returnedthe plastic beaker to scale balance, tared, and added required quantityof glycerol to the mask agent solution. The target glycerol content was1.5% by volume of masking agent solution. This corresponded to a targetweight of 1.5 g. (Note this corresponded to 25% Glycerol to PVP). Setbeaker on stirrer and stirred for at least 2 minutes. This masking agentsolution used for samples C.

Additional steps were used for samples D, i.e., additional PVP. Returnedthe plastic beaker to scale balance, tared, and added the requiredquantity of PVP to the masking agent solution. The target PVP contentwas 10% by volume of Mask solution. This corresponded to an additional 4g PVP added. (Note this effectively reduced the glycerol to PVP ratiofrom 25% to 15%). This masking agent solution was used for samples D.

Sealant Preparation

The silicone sealant dispersion as-supplied had a 30% solid content, thedispersion was diluted by an additional 100% of solvent. This reducedthe solid content to 15%. Additionally, a blue dye was added to thesilicone dispersion to provide a visual indication of the coverage anddepth of penetration of silicone into the fabric structure.

In particular, 20 ml of silicone dispersion was measured out from itscontainer, in the as-supplied state, and placed into a plastic beaker.An additional 20 ml of n-Heptane solvent was added. The mixture wasbeaked and was set on scales, tared, and drops of dye were added usingdropper. The recommended dye concentration range was 0.3% to 5%,depending of section thickness, therefore a target of 5% was set inorder to provide a strong blue colour for visualization. A deviationfrom this target was due to a calculation of the solid content being at30% rather than 15%, therefore the actual concentration of dye tosilicone was 10% rather than 5%.

Sample Preparation

The individual samples were prepared with masking agent formulationsaccording to the following table.

TABLE 8 No Mask 6% PVP 6% PVP + Glycerol (@25% of PVP) 10% PVP +Glycerol (@15% of PVP) Flat Fabric 71A 71B 71C 71D Crimped Fabric 70A70B 70C 70D

Samples B-D were immersed in the mask agent solution, as per the abovetable. The samples were assembled onto mandrel such that each fabric washeld at diameter by sized end bungs, but remained unsupported on theinner surface. The inner surface of each fabric was not in contact withthe mandrel to avoid affecting mask performance, location andconcentrations.

Dispersion drop assessment was undertaken as described below.

Each sample was fully coated with at least 2 coats of siliconedispersion. The intention was to ensure sufficient silicone was presenton the outer surface to effect a suitable coverage without concerns forlack of silicone during visual evaluations. Brush coating was done ontoa rotating graft on rotisserie at approximately one revolution persecond. Grafts were left overnight for solvent evaporation. Grafts wereleft to fully cure for recommended 72 hrs before being removed frommandrel for washing. The grafts were then placed in a delicate bag andput on 95° C. Tumble Machine Wash cycle for approximately 2 hours 30mins.

Samples were masked, coated, washed and cut opened flat.

Dispersion Drop Assessment

Prior to full coating, a single drop of polymer dispersion was appliedto each sample, and video recorded in order to visually assess if therewere noticeable differences in the behaviour of the dispersion on themasked fabric.

Sample A – No Mask. Slow spread of the single drop of polymer dispersionacross fabric. Appeared to be soaking into and through fabric

Sample B – 6% PVP Mask. Rapid spread of the single drop of polymerdispersion across fabric. Appeared to spread more readily than soakinginto and through fabric

Sample C – 6% PVP + 1.5% Glycerol Mask. First drop of the single drop ofpolymer dispersion had rapid spread across fabric. The second drop ofthe single drop of polymer dispersion was inconclusive, possibly due tosagging fabric holding the pool.

Sample D – 10% PVP + 1.5% Glycerol Mask. Inconclusive- possibly due tosagging fabric holding the pool

Dispersion Drop Assessment across face of the graft:

Sample A – No Mask. Slower spread of the single drop of polymerdispersion across fabric. Appeared to soak into fabric.

Sample B – 6% PVP Mask. Rapid spread of the single drop of polymerdispersion across fabric. Coverage was more uneven with pooling ofdispersion in valleys.

Sample C – 6% PVP + 1.5% Glycerol Mask. Fabric clearly resisteddispersion soaking in.

Sample D – 10% PVP + 1.5% Glycerol Mask. Fabric clearly resisteddispersion soaking in.

In summary, this Dispersion Droplet Assessment showed that even thelower concentration of masking agent, (Samples B, 6% PVP), appeared toinitiate a significantly different response when compared to anon-masked fabric.

A “pooling” effect was seen on the flat fabrics, samples 71C, 71D, wasmost likely a result of the excess dispersion being unable to run offthe fabric or through the fabric. This effect was perhaps also evidentin the crimped fabric, particularly Samples 70B, 70D, where there waspooling of the dispersion in the valleys, highlighted by the darkercolour, unlike the non-masked sample 70A, which appears far more uniformin colour/coverage.

Assessment of Sealant Coverage and Penetration

Following the wash cycle to remove the masking agent the grafts were cutlengthways to provide visualization of inner and outer surfaces. Eachgraft was visualized under optical microscopy on: (a) the outer surface– to confirm presence and uniformity of sealant coating; (b) the innersurface – to confirm presence or ingress of blue silicone, eitherthrough the fabric or between the yarn filaments; and (c) sectional view– to assess the level of penetration through the yarn bundles.

Results

Both samples without mask appeared to have permitted the dyed bluesilicone dispersion into the yarn bundles and penetrate to the innersurface while the application of the mask appears to have prevented thisingress on all samples.

TABLE 9 Mask Applied Penetration of Polymer to Inner Surface Flat FabricSamples 71A None Yes 71B 6% PVP No 71C 6% PVP + Glycerol No 71D 10%PVP + Glycerol No Crimped Fabric Samples 70A None Yes 70B 6% PVP No 70C6% PVP + Glycerol No 70D 10% PVP + Glycerol No

Photographs of crimped fabric sample 70D are provided in FIGS. 10 a-10 c. FIG. 10 a is a photograph of a portion of the cross-section of thetubular wall of the crimped fabric sample 70D. As shown in FIGS. 10 a-10c , the fabric sample or textile graft 30 includes an outer textilesurface 32, an opposed inner textile surface 34, and a textile wall 36disposed therein between. As shown in FIGS. 10 a and 10 c , a sealinglayer or coating 38 is disposed over the outer surface 32. Moreover, asshown in FIG. 10 a , the sealing layer or coating 38 extends into aportion of the textile wall. As shown in FIGS. 10 a and 10 b , the innersurface 34 is substantially, including completely, free of the sealinglayer or coating 38.

FIG. 11 shows a microphotograph or scanning electron microscope (SEM)photograph of a dried 40% PVP masking agent concentration applied to agraft sample 40. The dried masking agent slurry 44 gathered andencapsulated the yarn structure 42 and had cracks 46. It is evident thatthe silicone sealant would not be able to effect any permanent adhesionor encapsulation onto this surface fully encapsulated by the maskingagent.

The masking agent solution may encapsulate whole yarn bundles andindividual yarn fibers, depending on the concentration of the maskingagent solution. The higher concentrated masking agent solution(i.e. >30% w/w PVP, >20% w/w of PVP glycerol in water) seems to be toothick to flow into the yarn bundles and coat individual fibers, as seenin FIG. 11 . Additionally, high concentrations of masking solution driesas a thick, brittle mask layer, in which many samples develop microcracks 46 throughout the masking layer 44, as seen in FIG. 11 . If themasking agent solution concentration is low (< 10% w/w PVP, with orwithout glycerol in water), the masking agent may encapsulate the yarnbundle and individual fibers, however, a limitation of using a lowconcentration of masking agent solution may be lack of complete,consistent coverage around each yarn bundle and/or fiber. If this is thecase, portions of the fiber are exposed for a surface for potentialsealant attachment. Some results show, using low concentrations ofmasking agent solution, the sealant encapsulates and traps the maskinglayer; therefore, the masking is not fully washed out of the finalproduct. The key of an appropriate masking solution that works is tohave a controlled application process of a targeted concentration foreach application as set forth by the present invention.

The overall mechanism of masking agent may include two main concepts,depending on the size of the void or gap: (1) a physical effect formacro pathways (i.e. voids between yarn bundles) and (2) chemical effectfor micro pathways (i.e. voids between fibers and voids in micro crackswithin the masking layer).

-   (1) Physical Effect: Filling macro pathways is based on the physical    ability for the masking agent solution to penetrate and flow into    large voids between the yarn bundles. When the yarn bundles are    completely encapsulated with a masking agent layer, the masking    agent layer fills the voids between each yarn bundle and blocks    entry into the yarn bundle. In turn, the sealant would not be able    to penetrate within the macro pathways between each yarn or micro    pathways between each fiber due to the presence of masking to fill    these voids.-   (2) Chemical Effect: For micro pathways throughout the textile,    whether micro pathways refer to micro cracks within the masking    layer, micro voids between the yarn bundles or micro voids between    individual fibers, the chemical mechanism of the masking solution’s    repulsion effect or ability to repel away from the sealant causes    the sealant not to fill the micro voids. The repelling mechanism    occurs when the oleophobic sealant tries to come into contact or    close proximity with the highly hydrophilic masking layer. This is    proven using solution solubility theory and solubility parameters    developed by Joel H. Hildebrand. SI Hildebrand values (∂[SI])    demonstrate the masking solution and sealant solubility parameters    indicating the solvency behavior of their specific solvents when    they come into contact with one another. As noted in the Handbook of    Solubility Parameters, CRC Press, 1983, the solvents in the masking    solution (water and glycerol) are on the hydrophilic end of the    solubility parameter range, whereas the solvent of the sealant    (Heptane) is on the opposite end of the solubility parameter range.    The ∂[SI] of water is 48.0, ∂[SI] of glycerol is 36.2, and ∂[SI]    n-Heptane is 15.3.

Thus, the masking agents of the present invention hinder undesirablemigration of the sealant through, physical (e.g., blocking) andrepulsion mechanisms. Thus, it may be desirable to use a sealant(s)whose solvent(s) has a solubility parameter of less than about 20 ∂[SI],for example from about 10 ∂[SI] to about 20 ∂[SI] and a masking agentsolution(s) whose solvent(s) has a solubility parameter of greater thanabout 30 ∂[SI], for example from about 30 ∂[SI] to about 50 ∂[SI].

Conclusions

The use of blue dye in the silicone dispersion provided an excellentvisual assessment of silicone penetration into the fabric. Both samplescoated without prior mask application demonstrated substantial ingressof blue silicone sealant through the fabric to the inner surface. Allthree masking agent formulations appeared to substantially preventingress of silicone to the inner surface.

Silicone Sealing Tests for Commercial Vascular Grafts

The following equipment and materials were used to test sealingcommercial grafts according to the present invention.

-   8 mm crimped polyester fabric commercial graft-   14 mm crimped polyester fabric commercial graft-   Polyvinylpyrrolidone (PVP) Powder-   NuSil MED-6606 RTV Silicone-   N-Heptane-   Royal Blue Pigment-   De-ionised water-   Magnetic Stirrer

Coating Variable Ranges

The following values were used for the testing of the inventive sealingtechniques of the present invention.

-   PVP concentration in de-ionised water was varied on a weight basis    at 1%, 2%, 4%, 6%, 8%, 10%, 15%, 20%, 25%, and 30%.-   Glycerol and silicone dispersion concentration was tested at PVP    concentrations of 4%, 8%, 15%, and 30%. Glycerol concentrations were    used on PVP concentrations of 5%, 15%, and 30%. These concentrations    were percentage of glycerol to PVP.

The variations of PVP, glycerol, and silicone tested were as follows:

TABLE 10 Sample PVP Concentration (%) Glycerol Concentration (% of PVP)Silicone Concentration (%) 1 2 4 6 8 10 15 20 25 30 5 15 30 15 30 1 X X2 X X 3 X X ^(∗)4 X X 5 X X 6 X X ^(∗)7 X X 8 X X 9 X X ^(∗)10 X X^(∗)11 X X X 12 X X X 13 X X X 14 X X X 15 X X X ^(∗)16 X X X 17 X X X18 X X X ^(∗)19 X X X 20 X X X 21 X X X 22 X X X 23 X X X 24 X X X 25 XX X ^(∗)26 X X X ^(∗)Denotes samples to be applied to both types ofgrafts, i.e., First and Second graft samples.

Sample Preparation

Each sample was made from of a section of the commercial grafts. Thegrafts were first cut to length by first fully stretching the graft toremove the crimps, and then a section of 180 mm length was cut with asingle edge razor blade. Each sample was weighed.

Mask Preparation

A measured amount of de-ionised water was placed into a 100 ml plasticbeaker. A magnetic stirrer was placed into the de-ionised water. Whilestirring, PVP and glycerol (if any) were added. Stirring continued untilthere was no solute visible.

Masking Agent Application

The graft samples were coated by immersing the graft samples within themask solution and agitating the graft by gloved hands, so the sampleswere fully coated inside and out.

Once the grafts were fully coated, excess mask solution, if any, wasremoved. Next, each graft was attached to a mandrel by using cable ties.One end of the graft was secured to the mandrel by a cable tie, then thegraft was extended to 60% of its overall extended length (108 mm), andthe other end of the graft was secured to the mandrel by another cabletie. The mandrel was then placed horizontally on a rotating mount andallowed to air dry. Once dry, the masked grafts were weighed.

Sealant Preparation

The silicone dispersion was supplied as a 30% solid content. Additionalamounts of n-Heptane were added to reduce that solid content to 22.5%then 15. A blue dye was added to the silicone dispersion.

Sealant Application

The mandrel with the graft mounted was be placed on the rotary motor toslowly spin the graft. The sealant was applied with a paint brushstarting at one end and working to the other end. This was repeateduntil there was an excess of sealant dispersion on the graft. Once thetargeted level of silicone was applied onto the graft, the graft wastransferred to a rotating mount and allowed to air dry. Once dry, thesealed graft was weighed.

Masking Agent Removal

Once the grafts were fully dried, the masking agents were removed. Thiswas done by washing the grafts in a washing machine on a 90° C. wash(with no detergent). This caused the PVP to dissolve in the water andthus be removed from the graft. The 90° C. temperature also aided incomplete curing of the silicone. When the wash was complete, the graftswere hung up to air dry. After drying, the finished grafts were weighed.

Silicone Adherence

A good coating adhesion can also be demonstrated if the graft coatingmaintains its integrity in a high pressurised state. Pressure can beused as a measure over all sizes of grafts because most of the overallhoop stress is borne by the stiffer fabric material of the graft.Furthermore, most of the forces acting on the silicone coating fordelaminating it happen in the gaps between bundles of fibres as theweave structure does not change for different diameters of graft, thenthis area and consequently the force acting on that area will beconsistent. Therefore, irrespective of the size of graft the samepressure will produce the same force to delaminate the silicone coating.

To ensure the position of the bundles within the fabric are as uniformas possible over all diameters, the fabric was crimp removed so thegraft is in its fully extended shape. In accomplishing this, thepressure applied was above the pressure that it takes to fully extendthe graft. Since this pressure will be different for each size of graft,the graft that needs the highest pressure to fully extend itself (i.e.,the one of smallest diameter) will be used as a worst-case scenario.Once this worst-case pressure is determined, a factor of safety (FOS) isapplied and it is this FOS corrected pressure that is used as a minimumrequirement for all grafts. If the graft can be pressurised to this FOScorrected pressure with no visual signs of the coating delaminating(bubbles forming), then it can be deduced that the coating hassufficient and acceptable adhesion/integrity.

One method of testing for delamination is as follows:

-   Connect the graft to a pressure rig, ensuring one end is plugged;-   Slowly apply pressure to the graft;-   Stop at 120 mmHg (clinical pressure) and look for signs of    delamination (bubbles);-   Measure the leak rate and record it in mm/cm²/min;-   Increase the pressure in increments up to the FOS corrected figure    is reached;-   If any signs of delamination are visible at any point stop the test,    mark as failed;-   Hold at the FOS corrected pressure for 1 min; and-   If no signs of delamination are present, mark graft as pass.

The following pressure tests were conducted:

The grafts were pressurised with water to observe if there were anysigns of the silicone losing its bond from the graft. The pressure wasto be increased slowly to a maximum pressure of 600 mmHg. The adherencewas noted as follows:

-   0 – Silicone is well adhered to graft and showing no signs of    failure;-   1 – Graft reached the maximum pressure, but the leak rate has    visibly increased;-   2 – Silicone coating has started to fail, showing jets of water    coming from the graft; and-   3 – Silicone coating has failed, and a bubble has appeared on the    surface.

Penetration Depth

The effectiveness of the mask was determined by how far the siliconewicked through the fabric. Desirably, the silicone will sit on theoutside surface of the graft and not unduly penetrate the graftstructure. If the masking agent was not effective, then the silicone wasvisible within the fabrics and on the inside edge. To visualise this,the grafts were cut lengthways and a cross section was examined underhigh magnification.

The degree of penetration was noted as follows;

-   0 – Silicone only visible on the outer surface of the graft;-   1 – Silicone is visible between fibres of the graft but only up to    50% of the thickness;-   2 – Silicone is visible penetrating to the inside surface; and-   3 – Silicone visible everywhere, the entire graft structure is blue.

Test Results Summaries

TABLE 11 WEIGHT SUMMARIES Sample Name Weight of Graft Segment Initial(g) After Masking and Drying (g) After Sealant and Curing (g) AfterWashing and Drying (g) Amount of Masking Agent Applied (g) Amount ofSealant Applied (g) Ratio of Sealant to Masking Agent (g/g) 1 0.7030.714 1.496 1.485 0.011 0.782 71.1 2 0.714 0.739 1.484 1.46 0.025 0.74529.8 3 0.741 0.779 1.436 1.392 0.038 0.657 17.3 4 0.673 0.721 1.2391.182 0.048 0.518 10.8 A4 1.089 1.159 2.31 2.229 0.07 1.151 16.4 5 0.6890.778 1.199 1.1 0.089 0.421 4.7 6 0.698 0.778 1.216 1.129 0.08 0.438 5.57 0.694 0.813 1.454 1.319 0.119 0.641 5.4 A7 1.026 1.198 2.047 1.860.172 0.849 4.9 8 0.695 0.864 1.492 1.31 0.169 0.628 3.7 9 0.688 0.9391.541 1.276 0.251 0.602 2.4 10 0.663 0.969 1.537 1.207 0.306 0.568 1.911 0.739 0.778 1.382 1.339 0.039 0.604 15.5 A11 1.08 1.119 2.086 2.0410.039 0.967 24.8 12 0.658 0.712 1.262 1.201 0.054 0.55 10.2 13 0.7170.83 1.486 1.368 0.113 0.656 5.8 14 0.719 0.816 1.463 1.357 0.097 0.6473.7 15 0.717 0.853 1.513 1.367 0.136 0.66 4.9 16 0.701 0.888 1.502 1.2980.187 0.614 3.3 A16 0.896 1.103 1.731 1.503 0.207 0.628 3.0 17 0.7381.067 1.879 1.531 0.329 0.812 2.5 18 0.719 1.183 1.881 1.395 0.464 0.6981.5 19 0.705 0.754 1.502 1.446 0.049 0.748 15.3 A19 0.878 0.924 1.6821.632 0.046 0.758 16.5 20 0.717 0.759 2.063 2.016 0.042 1.304 31.0 210.709 0.809 1.46 1.355 0.1 0.651 6.5 22 0.741 0.844 2.121 2.007 0.1031.277 12.4 23 0.715 0.855 1.487 1.333 0.14 0.632 4.5 24 0.688 0.867 2.031.846 0.179 1.163 6.5 25 0.711 1.057 1.818 1.451 0.346 0.761 2.2 260.699 1.038 2.464 2.115 0.339 1.426 4.2 A26 1.356 2.058 4.448 3.6890.702 2.39 3.4

The ratio of sealant to masking agent on a gram to gram or weight drybasis varied from about 1:1 to about 70:1. Useful ratios also includeratios of sealant to masking agent from about 2:1 to about 20:1,including from about 2:1 to about 10:1, on a dry weight basis. Theseratios, however are non-limiting. The weight ratio of silicone (or othersealant agents) to PVP (or other masking agents) may vary from about0.1:1.0 wt. silicone (or other sealant agents) / wt. PVP (or othermasking agents) to about 100:1 wt. silicon (or other sealant agents) /wt. PVP (or other masking agents, desirably from about 1:1 wt. silicone(or other sealant agents) / wt. PVP (or other masking agents to about20:1 wt. silicone (or other sealant agents) / wt. PVP (or other maskingagents, more desirably from about 2:1 wt. silicone (or other sealantagents) / wt. PVP (or other masking agents to about 10:1 wt. silicone(or other sealant agents) / wt. PVP (or other masking agents.

TABLE 12 PENETRATION TEST RESULTS Sample Number PVP % Glycerol as % ofPVP Penetration Grading Scale 0-3 Comment 1 1 0 3 2 2 0 3 3 4 0 2 4 6 02 A4 6 0 2 5 8 0 2 6 10 0 1 7 15 0 2 A7 15 0 2 8 20 0 2 9 25 0 0Delaminated 10 30 0 0 Delaminated A10 30 0 Not Made 11 4 5 2 A11 4 5 212 4 30 2 13 8 5 2 14 8 30 2 15 15 5 1 16 15 30 0 A16 15 30 1 17 30 5 0Delaminated 18 30 30 0 Delaminated 19 4 15 2 A19 4 15 2 20 4 15 2 21 815 2 22 8 15 1 23 15 15 1 24 15 15 1 25 30 15 0 Delaminated 26 30 15 0Delaminated A26 30 15 0 Delaminated

The results, which are tabulated in order of PVP masking agentconcentrations, showed a clear correlation between higher levels of PVPand reduced penetration of the silicone sealant into the inner lumen ofthe graft samples.

In general, PVP mask concentration of 10% or greater prevented the bulkpenetration of silicone to more than 50% into the fabric thickness. Insome samples, they were small “fingers” or “slivers” of silicone evidentbetween the yarn bundles at the interstices created by warp and weftyarn bundles. Such interstitial silicone represented a very smallpercentage of the overall inner surface area of the fabric.

Adhesion Test Results

TABLE 13 Sample Number PVP (g) Glycerol as % of PVP Measured Leakage(ml/min) @120 mmHg Result 1 Measured Leakage (ml/min) @600 mmHg Result 3Adhesion grading Scale 0-3 1 1 0 0 0 0 2 2 0 0 0 0 3 4 0 0 0 0 4 6 0 0 40 A4 6 0 33 3 5 8 0 19 1 6 10 0 40 1 7 15 0 4 14 0 A7 15 0 31 1 8 20 012 46 1 9 25 0 Delaminated 3 10 30 0 >500 3 A10 30 0 11 4 5 0 1 0 A11 45 0 5 0 12 4 30 0 0 0 13 8 5 9 86 2 14 8 30 1 22 1 15 15 5 3 22 1 16 1530 1.5 1 A16 15 30 34 190 1 17 30 5 >1000 3 18 30 30 >1001 3 19 4 15 0 00 A19 4 15 4 27 0 20 4 15 0 0 0 21 8 15 0.5 5 0 22 8 15 0 3 23 15 15 1.511 0 24 15 15 0 3 25 30 15 Delaminated 3 26 30 15 Delaminated 3 A26 3015 Delaminated 3

The above results, which are tabulated in order of PVP masking agentconcentrations, show a clear correlation between higher levels of PVPand reduced adhesion of the silicone sealant to the fabric. Twomechanisms by which silicone penetrated into the inner surface of thefabric were observed, i.e., either through the yarn bundle fibers or bypassing between the gaps in the yarn bundles. The lower concentrationsof mask agent (>4% PVP) appeared to inhibit the flow of polymer throughthe yarn fibers, however it was not in all cases sufficient tosubstantially prevent the ingress of small “fingers” or “slivers” ofsilicone polymer between the gaps in the bundles, i.e., interstitialspaces between proximately juxtaposed yarns within the textile pattern.It appeared that slightly larger concentrations of mask agent (> 15%)was required to completely block the passage of silicone polymer throughbetween the gaps in the fiber bundles.

Assessment of Handling

The handling characteristics of grafts are the result of a series ofcomplex interactions between the fabric structure, the graft diameter,the crimp pitch and form, the thickness profile of the polymer sealantand the amount of penetration of the sealant into the yarn bundles.

The below assessment parameters, although subjective, aim to considerall of the following: bend radius at kink formation, flexibility, hoopstiffness (ability to remain fully open) and stretching.

A grading score (1 - 4) was be used to assess handling characteristics;

-   1 – Graft judged more flexible than reference sample.-   2 – Graft judged comparable to reference sample.-   3 – Graft judged to be stiffer than reference sample but with    useable characteristics.-   4 – Graft judged too stiff for comparable use.

The reference sample was considered to have excellent overall handlingand at least comparable to currently commercially available gelatinsealed grafts.

Polymer Sealant Coverage

The amount of polymer sealant coverage on each sample was reported inmg/cm² and was calculated by dividing the overall mass of polymerapplied to each individual graft by the surface area of the graft.Previous crimped prototypes have demonstrated both effective sealing andsuitable handling characteristics with polymer coverages of at leastabout 8 mg/cm² ranging up to about 14 mg/cm². Coverage levels above 14mg/cm² increased the overall stiffness of the handling characteristicsbeyond that of a standard gelatin sealed graft, however increasestiffness and therefore increased amount of polymer coverage may beadvantageous for some graft applications.

Tensile Extension Force

Samples were mounted between jaws of Lloyd Tensile Test machine withjaws spacing of 80 mm. The machine was zeroed and the jaws extended by20% (16 mm) and the maximum measured force was recorded.

The results recorded are tabulated below, ranked in order from low tohigh for force-to-extend by 20%.

These results demonstrated a strong correlation between handlingassessment and force-to-extend, with lower extension forcescorresponding to improved handling characteristics.

A review of the polymer coverage values indicated that coverage levelsof up to 40 mg/cm² might be considered in order to achieve comparablehandling characteristics to the reference sample (grading 2), asindicated by graft sample #15.

All grafts which demonstrated delamination of the polymer sealant duringpressurized adhesion tests are by a note (1) highlighted in italics.This list indicates that poor adhesion can result in low ExtensionForces and improved handling characteristics. This result supports thetheory that acceptable handling characteristics rely on lower levels ofpenetration of sealant into the yarn bundles.

TABLE 14 Sample No. Dia, mm Extended Length, mm Surface Area, cm2Polymer Coverage, mg/cm² Handling Assessment Grading, 1 to 4 Force toExtend by 20% (N) 18 (1) 8 130 32.7 43 1 0.29986 10(1) 8 125 31.4 38 10.37938 5 8 120 30.1 36 1 0.4067 25(1) 8 130 32.7 44 1 0.41064 6 8 13533.9 33 2 0.48247 16 8 130 32.7 40 2 0.48938 17 (1) 8 140 35.2 44 10.52805 8 8 130 32.7 40 2 0.53074 7 8 132 33.2 40 2 0.54057 9 (1) 8 12531.4 41 1 0.57061 13 8 140 35.2 39 2 0.58817 4 8 125 31.4 38 2 0.6015612 8 135 33.9 35 3 0.69369 15 8 135 33.9 40 2 0.71933 14 8 130 32.7 42 30.76625 3 8 135 33.9 41 3 0.78701 11 8 130 32.7 41 3 0.90773 1 8 13533.9 44 3 1.0072 19 8 135 33.9 43 3 1.0302 23 8 140 35.2 38 3 1.0372 2 8140 35.2 41 3 1.1116 21 8 125 31.4 43 3 1.1234 26(1) 8 134 33.7 63 41.1571 22 8 125 31.4 64 4 1.8936 24(1) 8 111 27.9 66 4 2.1711 20 8 11528.9 70 4 3.0235 64B 10 620 194.7 12.1 Reference Sample Note: (1)demonstrated delamination of the polymer sealant during pressurizedadhesion tests

Conclusions

Acceptable handling characteristics were achieved with lower levels ofpenetration of sealant into the yarn bundles. The use of the maskingagents to limit the amount of polymer penetration into textile fabriccan be utilized for improved handling characteristics. Polymer coveragelevels of up to 40 mg/cm² were demonstrated to achieve comparablehandling characteristics to the reference sample as assessed by surgeonusers.

Photographs of select samples from Tables 10-14 are reproduced in FIGS.12-19 . Description of these figures follow.

FIGS. 12 and 13 are SEM photographs of sample 2 from the above-describedTables. Sample 2 had the following characteristics:

-   Masking Solution: 2% PVP, 0 % Glycerol in water;-   Silicone Dispersant: 15% Silicone in heptane;-   Silicone Coverage: 41 mg/cm²;-   Silicone Penetration Grading: 3 (Silicone visible);-   Silicone Adherence Grading: 0 (Silicone is well adhered to graft and    showing no signs of failure);-   Measured Leakage at 120 mmHg: 0 ml/min;-   Measured Leakage at 600 mmHg: 0 ml/min;-   Handling Assessment: 3 (Graft judged to be stiffer than Reference    but with useable characteristics); and-   Tensile Force to Extend Graft by 20%: 1.112 N.

FIG. 12 is a SEM photograph of a cross-section of the textile 50 ofSample 2. The outer surface 52 of the textile 50 was fully coated withsilicone sealant 56. Fiber bundles 58A were fully encapsulated by thesilicone sealant 56. The silicone sealant was disposed throughout thecross-section of the fiber bundle or the multi-filament yarn 58. Asdepicted in FIG. 13 , the inner textile surface 54 also had noticeableamounts of silicone sealant 60 at the fiber bundles 58.

FIGS. 14 and 15 are photographs of sample 9 from the above-describedTables. Sample 9 had the following characteristics:

-   Masking Solution: 25% PVP, 0 % Glycerol in water;-   Silicone Dispersant: 15% Silicone in heptane;-   Silicone Coverage: 41 mg/cm²;-   Silicone Penetration Grading: 0 (Silicone only visible on the outer    surface of the graft);-   Silicone Adherence Grading: 3 (Delaminated, Silicone coating has    failed, and a bubble has appeared on the surface);-   Measured Leakage at 120 mmHg: Delaminated;-   Measured Leakage at 600 mmHg: Delaminated;-   Handling Assessment: 1 (Graft judged more flexible than Reference    Sample); and-   Tensile Force to Extend Graft by 20%: 0.571 N.

FIG. 14 is a photograph of a cross-section of the textile 50 of Sample9. The outer surface 52 of the textile 50 was fully coated with siliconesealant 56. Individual textile bundles 58 were general free of siliconesealant penetration. There was, however, delamination of the siliconesealant 56 from the textile fibers at the outer surface as noted bydelamination spaces. As depicted in FIG. 15 , the inner textile surface54 and all fiber bundles 58 thereat were free of any noticeable amountsof silicone sealant 60.

FIGS. 16-18 are SEM photographs of sample 7 from the above-describedTables. Sample 7 had the following characteristics:

-   Masking Solution: 15% PVP, 0 % Glycerol in water;-   Silicone Dispersant: 15% Silicone in heptane;-   Silicone Coverage: 40 mg/cm²;-   Silicone Penetration Grading: 2 (Silicone is visible penetrating to    the inside surface);-   Silicone Adherence Grading: 0 (Silicone is well adhered to graft and    showing no signs of failure);-   Measured Leakage at 120 mmHg: 4 ml/min;-   Measured Leakage at 600 mmHg: 14 ml/min;-   Handling Assessment: 2 (Graft judged comparable to Reference Sample    64B); and-   Tensile Force to Extend Graft by 20%: 0.541 N.

FIG. 16 shows an SEM photograph of a cross-section of the textile 50 ofSample 7. As shown in FIG. 16 , the textile fiber bundles 58 on theouter textile surface 52 were penetrated and encapsulated with siliconesealant 56. The textile fiber bundles 58 at the inner textile surface 54were free from silicone sealant 60 penetration. As shown in FIGS. 17 and18 , the silicone sealant 56 penetrated and encapsulated the textilefiber bundles 58 at the outer textile surface. The fiber bundles 58 atthe inner textile surface 54 were free from silicone sealant 56.

FIG. 19 is an SEM photograph of sample 15 from the above-describedTables. Sample 15 had the following characteristics:

-   Masking Solution: 15% PVP, 5% Glycerol in water;-   Silicone Dispersant: 15% Silicone in heptane;-   Silicone Coverage: 40 mg/cm²;-   Silicone Penetration Grading: 2 (Silicone is visible penetrating to    the inside surface);-   Silicone Adherence Grading: 1 (Graft reached the maximum pressure,    but the leak rate has visibly increased);-   Measured Leakage at 120 mmHg: 3 ml/min;-   Measured Leakage at 600 mmHg: 22 ml/min;-   Handling Assessment: 2 (Graft judged comparable to Reference Sample    64B); and-   Tensile Force to Extend Graft by 20%: 0.719 N.

FIG. 19 is a SEM photograph of a cross-section of the textile 50 ofSample 15. The silicone sealant 56 encapsulated the outer fibers of thefiber bundles 58 at the outer textile surface 2. The fiber bundles 58 atthe inner textile 54 were free from penetration of the silicone sealant56. Dyed silicone sealant (not shown) was visible ay the inner surface54.

Glycerol Hydration of Masking Agents

The use of glycerol within different masking agent formulations has beendemonstrated on multiple formulations with the aim of hydrating orplasticizing the (PVP) masking agent and improving its ability to coverand fill the yarn structure and prevent the sealant dispersion fromingress to the inner surface.

Masking Agent Sample Preparation

Masking agents were prepared using following method:

A target weight of PVP (MW 10,000) was introduced in a plastic beaker ona scale balance. A 100 ml masking agent solution was prepared at atarget mass of 10 g PVP (10% concentration). The target volume ofde-ionised water was introduced into a 100 ml plastic measuringcylinder. A target volume of 90 ml was required. The de-ionised waterwas added into the PVP in plastic beaker. A magnetic stirrer rod wasplaced in the water, and the beaker was placed on the magnetic stirrer.The magnetic stirrer was turned on at a speed of 350-450 RPM, thestirrer was centered in the beaker. The stirring was done at roomtemperature. Stirring continued until there was no visible PVP solute,but for at least 2 minutes. After stirring the masking agent solution,it can be removed from stirrer and used for control sample preparation.

Additional steps were used for subsequent samples with added glycerol.The plastic beaker was returned to scale balance, tared, and therequired quantity of glycerol was added to the masking agent solution.The target glycerol content was calculated as a percentage by mass ofthe PVP. The target weight of Glycerol added at each stage was 1 g,corresponding to cumulative weights of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10g. Each beaker was stirred for at least 2 minutes after each addedquantity of Glycerol.

A summary of the samples prepared are shown below.

TABLE 15 Sample Ref. Volume of water PVP Weight PVP % w/v GlycerolWeight Glycerol as % of PVP Control 90 ml 10 g 10% 0 0 A) 10% Glycerol90 ml 10 g 9.9% 1 g 10% B) 20% Glycerol 90 ml 10 g 9.8% 2 g 20% C) 30%Glycerol 90 ml 10 g 9.7% 3 g 30% D) 40% Glycerol 90 ml 10 g 9.6% 4 g 40%E) 50% Glycerol 90 ml 10 g 9.5% 5 g 50% F) 60% Glycerol 90 ml 10 g 9.4%6 g 60% G) 70% Glycerol 90 ml 10 g 9.3% 7 g 70% H) 80% Glycerol 90 ml 10g 9.3% 8 g 80% I) 90% Glycerol 90 ml 10 g 9.2% 9 g 90% J) 100% Glycerol90 ml 10 g 9% 10 g 100%

Dispersion Drop Castings

Three individual drops of each masking agent formulation were cast ontoa dark coloured sheet to allow visual observation during the dryingprocess. The drying was accelerated by using a desk fan at roomtemperature

Assessments of the masking agents after drying were as follows:

TABLE 16 Sample Ref. Assessment after 12 hours Assessment after 96 hoursControl Looked white, Dry to touch Dry, Brittle A) 10% Glycerol Lookedhydrated, Dry to touch Looked hydrated, Dry to touch B) 20% GlycerolHydrated, Soft, Tacky to touch Hydrated, Soft, Tacky to touch C) 30%Glycerol Very Sticky to touch Sticky to touch D) 40% Glycerol Sticky,still wet Sticky, still wet E) 50% Glycerol Wet to touch Wet to touch F)60% Glycerol Wet to touch Wet to touch G) 70% Glycerol Wet to touch Wetto touch H) 80% Glycerol Wet to touch Wet to touch I) 90% Glycerol Wetto touch Wet to touch J) 100% Glycerol Wet to touch Wet to touch

Conclusions

The control masking agent formulation (e.g., PVP-only) dried out fullywithin a few hours and became brittle. Use of this PVP-only maskingagent may result in a stiff graft structure once mask is applied anddried. The use of 10% glycerol helped to hydrate the PVP masking agentsolution, and appeared dry after 12 hours. A masking agent solutionconsisting of 20% glycerol retains some hydration at 12 hours and issoft/ deformable to touch. A range of between about 1% and about 30%glycerol to PVP, by weight, provides appropriate ranges for use with thepresent invention.

Moreover, the present invention is not limited to vascular prostheses inconduit-type shapes. The methods, coatings, and masking agents of thepresent invention may suitably be used with other textile products,including medical and non-medical (e.g., non-implantable) textileproducts. Other medical products may include ventricular assist devices,artificial heart conduits, medical sheets, patches, meshes, and thelike. Non-medical textiles may include, but are not limited to,clothing, geotextiles, transportation textiles, military and/or defensetextiles, safety and/or protective textiles, sports and/or recreationtextiles, and the like. Further, textile products are not limited totubular conduits, but may be of any shape including, but not limited tofor example, sheets and/or tapes (e.g., two-dimensional products), oreven three-dimensional shaped products other than conduit-shapedproducts.

Useful polymeric materials and/or for fibers for non-medical ornon-implantable textiles may include, but are not limited to,polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE),expanded polytetrafluoroethylene (ePFTE), polyolefins, polyesters,poly(ether amides), poly(ether esters), poly(ether urethanes),poly(ester urethanes), poly(ethylene-styrene/butylene-styrenes), andother block copolymers. Useful animal fibers for the non-medical ornon-implantable textiles of the present invention may include, but arenot limited to, wool, alpaca, angora, mohair, llama, cashmere, and silk.Useful natural fibers may include, but are not limited to, linen, cottonbamboo, hemp, corn, nettle, soy fiber, and the like.

The masking agents and/or the sealants may be applied by brushing,spray-coating, dipping or immersing, and the like. The presentinvention, however is not limited to such techniques, and othertechniques, such as chemical deposition, vapor deposition, chemicalvapor deposition, physical vapor deposition, printing and the like, maysuitably be used. These techniques are generally suitable for medicaltextiles. However, for large commercial scale textile production,including non-medical textiles, other techniques may also be used. Forexample, coating and/or masking materials for textile sheets orsubstrates may be applied by squeegee type coating, roller coating,knife coating, nip coating, dip coating, cast coating, chemicaldeposition, vapor deposition, and the like. Moreover, printingtechniques, such as roller printing, stencil printing, screen printing,inkjet printing, lithographic printing, 3D printing, and the like may beused with the present invention for applying the masking agents and/orthe sealing agents. Furthermore, mechanical devices may be employed tocontrol the depth of penetration of the masking agent and/or sealingagent into the wall of the textile substrate of graft. For example, witha tubular graft an expandable balloon may be to control the depth ofpenetration of the masking agent into the graft wall.

Selective Mask Agent Removal Techniques

If desired, masking agent may be selectively removed, either in total orpartially, from portions and/or surfaces of textile material of thepresent invention. One technique for selectively removing the maskingagent is through the use of a particulate solid flowing against aportion or a surface of the textile. The particulate solid may ablatethe masking agent to remove it from the portion and/or surface of thetextile. Such flow of a particular solid is typically performed with aflow media, such as air, but other flow media, including gasses, vapors,or liquids, may be used.

Desirably, the particulate solid has physical properties that will notunduly harm or adversely affect the textile graft or substrate of thepresent invention. One useful particulate solid is sodium bicarbonate.Other useful particulate solids include, but are not limited to, sodiumchloride, sugar, magnesium sulphate, potassium chloride, calciumcarbonate (including calcite), and talc. Sodium bicarbonate has a Moh’shardness of about 2.5. Other materials having a Moh’s hardness fromabout 1 to about 5 may be used, more desirably a Moh’s hardness fromabout 3 to about 4 may be used.

When the particulate solid is being used to remove the water solublemasking agent of the present invention, it may be desirable to use awater soluble particulate solid, such a sodium bicarbonate. Use of awater soluble particulate solid may be useful in the removal of thesolid particulate from the textile after ablation, for example bywashing or spraying with water and/or a solvent, either before or afterthe application of the sealing agent or sealant. Any suitable organic orinorganic solvent may be used to wash or spray the textile.

The particulate solid may have any useful particle size. In general, thelarger the particle size or the coarser the material may offer greaterablating potentials. Useful particle sizes may vary from an averageparticle size from about 10 microns to about 1,000 microns, includingfrom about 50 microns to about 350 microns, in particular an averageparticle size from about 100 microns to about 300 microns. Averageparticle sizes from about 250 microns to about 300 microns have beenused to ablate masking agents from textiles substrates of the presentinvention. Such average particle sizes may be on a weight basis or avolume basis depending upon the test method for measuring particle size.

Preferably the particulate solid or ablating material should have acrystalline structure and geometry with a particle size of greater thanabout 10 microns. A wide variety of substances could be used to abradethe mask. Any granular material which is capable of being pressureblasted when entrained in a pressurised flow of gas may be used. Thegranular material may have a hardness which exceeds that of the maskingagent. Preferably the blasting material should be water soluble and nontoxic. Examples of particularly useful materials include, but are notlimited to, sodium bicarbonate, sodium chloride, sugar, magnesiumsulphate, potassium chloride, and combinations thereof.

Force of the ablating materials striking a surface also effects theablating of the masking agent. Higher ablating pressures offer greatermasking agent removal potentials, but may present higher potentials fordamage of the textile pattern or yarns within the textile patterns.Desirably, solid particulates for ablating the textile substrates of thepresent invention are sprayed at a pressure from about 10 pounds persquare inch force (psig) (or about 70 kilopascal gauge or kPa gauge) toabout 50 psig (or about 340 kPa gauge). Useful spraying pressuresinclude from about 20 psig (or about 140 kPa gauge) to about 50 psig (orabout 340 kPa gauge), more desirably from about 20 psig (or about 140kPa gauge) to about 30 psig (or about 210 kPa gauge).

High ablating pressures, such as substantially greater than 50 psig (or340 kPa gauge) may create multiple fibre breakages on the outer surfaceof the textile graft. While it may not be desirable to overly weaken thetextile graft, textile grafts are typically over-engineered and are muchstronger than required, so some yarn surface damage may be tolerates.Indeed, such broken outer yarn filaments, if present, may create atexturized effect on the outer surface of the coated graft, which mayimprove, for example, the general handling of the graft and adhesion ofthe sealant coating.

The present invention, however, is not limited to the use of solidparticulate matter for ablating the masking agent from textilesubstrates, and other techniques may suitably be used. For example, abrush, such as a bristle brush, may be used to selectively removemasking agent.

Details of selective masking agent removal are further described belowin Table 17.

TABLE 17 Abrading Technique Soda Blasting Static Brushing RotatingBristle Brushing Methods Sodium bicarbonate (Ecostrip) with an averageparticle size of 285 microns was sprayed at 20 - 50 psig (140 - 340 kPagauge) onto a rotating graft. A hand held, bristle brush (0.5 mm bristlediameter, 15 mm bristle length) was held static against a rotatinggraft. A counter rotating brush (0.4 mm bristle diameter, 30 mm bristlelength) was brushed alongside the rotating graft. Graft Samples (A) PETwoven graft, crimped, straight (10 mm ID) with 35% PVP +15% GlycerolMask (B) PET woven graft, crimped, straight (14 mm ID) with 20% PVP +15%Glycerol Mask (A) PET woven graft, crimped, straight (14 mm ID) with 20%PVP +15% Glycerol Mask (A) PET woven graft, crimped, straight (14 mm ID)with 20% PVP +15% Glycerol Mask

Conclusions

Soda blasting (sodium bicarbonate) abrading methods for removing maskingoff the outer surface worked well, while leaving the inner masking agentsurface intact. Soda blasting is compatible with complex textile orgraft geometry, including being particularly suitable for use on acrimped graft. Some non-limiting parameters in soda or particulateblasting are grain particle size and blast pressure. The use of soda orparticulate blasting to improve adhesion levels of the silicone to PETyarn has been demonstrated. A crimped graft using a 20% PVP mask may,under certain conditions show delamination, however, this graft hadimproved levels of silicone adhesion when ablated with sodiumbicarbonate under the same conditions. Graft inner surfaces appearedfully intact after blast abrasion. The sealing agent or sealant,however, is not limited to the use of silicone, and other sealing agentor sealant formulations may include, but not limited to, silicone, roomtemperature vulcanizing silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, polycarbonate, andcombinations thereof with or without solvent; and the masking agent,however, is not limited to the use of polyvinylpyrrolidone, and maskingagent formulations may include, but not limited to, polyvinylpyrrolidoneglycerol, methyl cellulose, poly(ethylene glycol), polyethylene oxide,poly(ethylene glycol) hydrogel, and combinations thereof with or withoutwater or other solvent.

Bristle brushing showed some disruption to the outer mask surface.Static bristle brush and rotating bristle brush abrading methods withrotating graft may have a disadvantage with respect to controlling thelevel of force applied to the graft. For crimped grafts, larger brushcontact surfaces may tend to focus the brushing action at the graftpeaks, leaving valleys with limited abrasion.

Further details of the sodium bicarbonate abrasion tests are describedbelow in Table 18.

TABLE 18 Soda Blast Pressure (psig) PVP Mask Concentration Broken YarnsIdentified (Yes/No) Yarn Damage Ranking (0 - 3)^(∗) 20% PVP + 15%Glycerol 50% PVP (No Glycerol) 20 X No 0 25 X No 0 30 X Yes 1 35 X Yes 140 X Yes 2 45 X Yes 2 50 X Yes 3 ^(∗)Yarn Damage Ranking 0 - No brokenyarns identified 1 - Localized single yarn breakages, 2 - Localizedmultiple yarn breakages 3 - Broken yarn filaments over majority ofsurface.

The utility of abrading the outer surface layer of masking agent tocontrol masking coverage on a graft’s exterior has been demonstrated.Such abrading may be used in preparation for subsequent coating and toincrease silicone adhesion to PET graft. Ablating and other removaltechniques allow for heavier application of masking agents, therebyproviding greater assurance levels that the inner surface of the graftis free, including substantially free and completely free, of anysilicone ingress during the application thereof. Abrading methods testedincluded soda blasting, static brushing, and rotating bristle brushing,but other techniques may be used. The ablation techniques may be usedwith any suitable masking agent, such as polyvinylpyrrolidone glycerol,methyl cellulose, poly(ethylene glycol), polyethylene oxide,poly(ethylene glycol) hydrogel, and combinations thereof with or withoutwater or other solvent, and with any suitable The sealing agent orsealant, such as silicone, room temperature vulcanizing silicone,thermoplastic polyurethane, aliphatic polycarbonate, one or morethermoplastic elastomers, polycarbonate, and combinations thereof withor without solvent.

Sealant or Silicone Application by Spraying Using Forced Air

Target silicone coverage on the PET woven grafts for these examples was14 mg/cm². The dispersion mass of silicone based on the target coveragewas calculated and loaded into an application syringe. Each sample graftwas sprayed using a one-way pass (right to left) method withapproximately 45 second delay between each spray pass to allow initialflash-off of excess solvent from the sealant composition. For siliconespraying, spray pressure was 11 pounds per square inch (psig) (or about76 kPa gauge), traverse speed was 20 mm per second, and rotation speedof graft was typically from about 100 revolutions-per-minute or RPM toabout 150 RPM. Higher rotations speeds, for example 300 RPM, were alsotested. The spray passes were repeated until sealant volume in thesyringe was used or applied.

PET Graft Sample Descriptions

Graft Samples:

-   (A) Samples #111 - 119: Straight woven PET crimped graft (14 mm ID),-   (B) Samples #120 - 121: Valsalva PET graft (22 ×20 mm ID)

Masking Agent Composition

Mask Formulation: 12% PVP with 15% Glycerol (as% of PVP) (Sample #114dyed blue).

The masking agent solution was applied via immersion dipping of abovegraft samples 111 to 120 with rigorous manual manipulation. Excessmasking was removed via manual squeezing between fingers for thestraight grafts and between a roller press for the Valsalva grafts.

Sealant Agent Composition

MED6-6606 (NuSil) silicone dispersion in heptane, 15% solid content, wasused. Samples Nos. 111 and 115 further contained blue dye.

Spray Results

Results of applying an even silicone coating across the length of thegraft using forced air spraying are described below in Table 19.

TABLE 19 Position of Sample 6 5 4 3 2 1 #111 Length (mm) 71 68.5 67.568.5 68.5 57 Weight (g) 0.77 0.733 0.717 0.716 0.717 0.632 Average SDWeight/Length (mg/mm) 10.85 10.70 10.62 10.45 10.47 11.09 10.70 0.22#112 Length (mm) 71.5 71.5 71.5 71.5 72.5 73 Weight (g) 0.784 0.772 0.770.777 0.779 0.775 Average SD Weight/Length (mg/mm) 10.97 10.80 10.7710.87 10.74 10.62 10.79 0.11 #113 Length (mm) 73.7 71.5 70.7 72.7 71.572.5 Weight (g) 0.778 0.759 0.78 0.815 0.799 0.826 Average SDWeight/Length (mg/mm) 10.56 10.62 11.03 11.21 11.17 11.39 11.00 0.31Note: SD is an abbreviation for standard deviation

Silicone Coated PET Graft Leak Tests (ISO 7198 - Whole Graft LeakTesting) are described below in Table 20.

TABLE 20 Sample # Silicone Coverage (mg/cm²) Permeability (ml/min/cm²)Comments on Leakage at 120 mmHg Delamination at 600 mmHg # 111 10.3 0.00Near water tight Yes # 112 10.5 0.04 Heavy Beading from Peaks No # 11310.5 0.06 Heavy Beading from Peaks No # 114 10.9 0.02 Beading No # 11614.2 0.01 Bubble delamination at seams Yes # 117 14.0 0.49 Heavy Beadingfrom Peaks No # 118 14.2 0.02 Beading at Peaks Yes # 119 15.3 n/a FullDelamination n/a # 120 13.4 0.58 Heavy Beading from Peaks & Delaminationat Bulge n/a # 121 12.1 0.34 Delamination at Bulge n/a

Silicone coated sample # 111 demonstrated no leakage at 120 mmHg, buthad bubble delamination at the peaks of the crimps and along the graftseam at 250 mmHg. Silicone coated sample # 112 demonstrated heavybeading from peaks at 120 mmHg and no delamination at 600 mmHg. Siliconecoated sample # 114 demonstrated beading from peaks at 120 mmHg and nodelamination at 600 mmHg. Silicone coated sample # 116 demonstratedbubble delamination along both graft seams at 120 mmHg and expandedbubble delamination along the seams at pressures > 120 mmHg. Siliconecoated sample #117 and #118 demonstrated heavy beading and leakage atthe peaks of the crimps during leak testing at 120 mmHg. Silicone coatedsample # 119 demonstrated initial delamination at graft seams thenquickly migrated to cover the full circumference of the graft duringleak testing at 120 mmHg. Silicone coated Valsalva samples # 120 and #121 demonstrated heavy beading and leakage at the peaks of the crimpsduring leak testing at 120 mmHg. Bubble delamination on the Valsalvagraft occurred near the transition of the bulge and the crimped body ofthe graft.

Observations and Conclusions

Spray coating methods using forced air provided a consistent and an evencoverage of silicone deposition throughout the length of the woven PETcrimped graft.

For Samples # 111-114, spray parameters had a 25% dispersion loss duringthe spraying process, where actual silicone coverage (10.5 mg/cm²) wasless than targeted coverage (14 mg/cm²). This dispersion loss isbelieved to be due to the forced air flow from the fume hood. It may bebeneficial to shield the graft and nozzle from the high extraction flowto reduce direct dispersion loss during spraying. This dispersion losswas accounted for during preparation of Samples # 116-121. For Samples #116-121, actual silicone coverage was between 12.1 and 15.3 mg/cm².These results show that the process has a reasonably good level ofcontrol and repeatability.

Average water permeability of silicone sprayed grafts was 0.03ml/min/cm². All silicone coated graft samples demonstrated water beadingfrom the crimped graft peaks during the leak testing at 120 mmHg. Underthese test conditions, 12% masking agent concentration may be too highto permit full and reliable adhesion of the silicone to the graftwithout potential delamination.

During pressure leak testing, the weakest attachment strength ofsilicone to the textile or fabric appeared consistently to be at theseams of the woven PET graft. Samples # 111, 116, and 118 demonstrated abubble delamination on opposing graft seams. These observations suggestthat the masking coverage may be affected by the localized variation inthe weave structure on the seams of the graft. While not being bound byany particular theory, it is proposed this is due to the locally tightweave structure of the graft seam which presumably retains a higher maskconcentration and/or offers a less texturized surface for the siliconeattachment.

As used herein a seam may refer to a discontinuity or a controlledchange in a textile pattern along a portion of a textile graft, such asfor example an edge of a flat woven tubular graft. The seam may becaused by a change in yarn density. The change in yarn density may beinfluenced by adding or dropping yarn ends during weaving or the like.The change in yarn density may also be influenced by changing relativespacing of the yarns within the textile pattern.

For the Valsalva samples # 120 and 121, the predominant area fordelamination was on the Valsalva bulge adjacent to the transition to thecrimped body. Although only hypothesis and not being bound by suchhypothesis, it is believed that the masking agent wiping processemployed was less effective at removing excess masking agent from thislocalized area, as the non-crimped bulge passed through the rollers andtransitioned to the crimped body. The process to remove excess maskingmay therefore, if desired, be modified to accommodate any transitionsbetween graft structure, e.g. crimped to non-crimped or additionalbranches, etc. For example, selective application of masking agent maybe used where such portions of the graft may have lower level of appliedmasking agent as compared to the other portions of the graft.Alternately, or in addition to, selective removal of excess agent may beapplied, including selective removal at just desired portion of thegraft.

Thus, the spraying of the textiles of the present invention with the useof forced air has been demonstrated as an effective method ofcontrollably adding sealant or sealing agent. Any suitable agent orsealant, such as, but not limited to, silicone, room temperaturevulcanizing silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, polycarbonate, andcombinations thereof with or without solvent may be used.

Silicone Spraying Trials Using Ultrasonic Application Techniques

The spraying silicone using ultrasonic on the exterior surface of awoven PET graft was investigated. Woven PET straight grafts were spraycoated using a target silicone coverage. The ability for the sprayer toapply an even silicone coating across the length of the graft usingultrasonic techniques was investigated. The silicone coated grafts weretested for leakage.

Spray Equipment and Methods

Automatic spraying system that utilized ultrasonic nozzles to atomizesolutions to spray coat various substrates was used. Three benchtopmodels of the system included: (1) 400 (400 × 400 mm stage), (2) prism500 (500 × 500 mm stage), and (3) prism 800 (800 × 800 mm stage). Listedbelow were the variables for the spraying experiments.

-   1. Silicone MED6-6606 (NuSil) Percent Solids Concentration:    -   a. Original Percent Solids: 30%.    -   b. Diluted Percent Solids: 24% (4:1 MED6-6606: Additional        Heptane).    -   c. 2 mL of MED51-4900-7 COLOR MASTER BATCH FOR LIQUID SILICONE        ELASTOMERS was added to approximately 90 mL of diluted solution.-   2. Head Type – Frequency of ultrasonics: ILDS Ultrasonic head from    Ultrasonic Systems, Inc., Haverhill, MA, USA.-   3. Flow Rate – Syringe pump driven: 2.1 mL/min.-   4. Head speed: 7-21 mm/sec.-   5. Head Height: 10 - 20 mm.-   6. Air Direction Pressure: 10 - 15 psig (or about 70 - 105 kPa    gauge).-   7. PM: 500.-   8. Stroke Length: 110 mm.-   9. # of Passes: 4-16 (Dependent of flowrate, and amount needed to    deposit).-   10. Time (Dependent on number of passes and head speed).

Methods

For samples 64, non-crimped PET grafts (about 14 mm ID) were cut intoabout 8 to 10 cm segments. Each segment was loaded onto the spindlemandrel and secured with tape. The recipes with parameters listed belowin the test matrix were completed for each sample.

For samples 45, crimped PET grafts (about 14 mm ID) were stretched outto 28 cm and cut into 4 equal parts, approximately 110 mm total whenfully stretched. Each sample was placed on the spindle mandrel andcoated with the below parameter listed in the test matrix above. Eachsample was evaluated for its ability to seal according to ISO 7198:Whole graft permeability.

Results

TABLE 21 PET Graft Sample Silicone Spray Coating Parameters SampleNumber Flow Rate Head Speed Head Height Air Dir Press RPM # Passes TimeTop Oven Temp 64-7A 2.1 21 20 10 500 12 0:01:07 RT 64-7B 2.1 21 20 10500 12 0:01:07 RT 64-7C 2.1 21 20 10 500 8 0:00:45 RT 64-11A 2.1 21 2010 500 8 0:00:45 RT 64-11B 2.1 21 10 10 500 8 0:00:45 RT 64-11-C 2.1 2110 15 500 8 0:00:44 RT 64-12A 2.1 21 10 15 500 12 0:01:07 RT 64-12B 2.110.5 10 15 500 12 0:02:10 RT 64-12-C 2.1 10.5 10 15 500 6 0:01:05 RT64-8A 2.1 21 20 10 500 8 0:00:45 55 64-8B 2.1 21 20 10 500 4 0:00:22 RT64-8C 2.1 21 20 10 500 4 0:00:22 55 45-17A 2.1 21 20 10 500 12 0:01:07RT 45-17B 2.1 21 20 10 500 8 0:00:44 RT 45-17C 2.1 21 20 10 500 160:01:29 RT 45-17D 2.1 21 10 10 500 12 0:01:07 RT 45-18A 2.1 21 10 10 5008 0:00:45 RT 45-18B 2.1 21 10 10 500 16 0:01:29 RT 45-18C 2.1 21 20 10500 4 0:00:22 RT 45-18D 2.1 14 20 10 500 8 0:01:05 RT 45-21A 2.1 7 20 10500 4 0:01:04 RT 45-21B 2.1 10.5 20 10 500 12 0:02:10 RT 45-21C 2.1 2120 10 500 8 0:00:45 RT 45-21D 2.1 21 20 10 500 16 0:01:29 RT 45-14 2.121 20 10 500 15 0:03:13 RT Note: “RT” is room temperature

TABLE 22 Digital Measuring Microscope Cross-Sectional Penetration DepthChart Graft Number Coating Amount Target Si Thickness -Fabric Surface(µm) Fabric Thick (µm) Penetration Depth (µm) Penetration Depth (%)45-17C 10.8 mg/cm² 10 192 0 231 146 0 233 199 0 150 252 78 31% 45-18D 8mg/cm² 45 95 0 0% 13 108 0 0% 65 130 0 0% 20 171.65 60.112 35% 24 164 6238% 39 60 0 0% 13 169 69 41% 38 184 57 31% 37 73 0 0% 45-21B 16 mg/cm²85 127.3 170 146 214.1 54.1 25% 190 38.7 20% 64-11A 5.4 mg/cm² 24 16651.5 31% 0 194 101 52% 97.8 29 64-12B 16 mg/cm² 110 0 130 130 0 151 1730 160 166 95 57% 125 131 0 64-12C 8 mg/cm² 63 220 0 42 164 0 91 60 0 10226 0 29 189 75 40% 93 85 0 16 190 118 62% 91145 sample 14 Unknown 23123 45 37% 45 207 0 32 159 0 0 174 75 43% 28 96 0 65 109 0 11 96 0 18182 63 35% Noanix Unknown No Coating Visible

TABLE 23 Permeability and Delamination Testing (ISO 7198 - Whole GraftLeak Test) Pressure (psig) 2.4 Ran for 30 secs Number Coat (mg/cm^2)Crimp/Straight Leak? Amount leaked (mL) Delamination 45-18C 2.7 CrimpYes 440 No 45-17B 5.4 Crimp Yes 256 No 45-21A 8 Crimp Yes ~15 No 45-17C10.8 Crimp No 45-21B 16 Crimp No 64-8B 2.7 Straight Yes 467 No 64-11A5.4 Straight Yes 470 No 64-12C 8 Straight No 0 No 64-12B 16 Straight No0 No

Observations and Conclusions

Spray coating using Ultrasonic and force air shaping with a spinningsubstrate on 14 mm inner diameter non-crimped and crimped woven PETgrafts provided an even coverage when assessed visually, a 24% solidssilicone content was used with Ultrasonic. No masking agent was usedbefore silicone was applied.

Using ultrasonic spraying methods, silicone coverage levels are directlycorrelated to speed of head, ultrasonic frequency, rotational speed ofgraft, height of spray nozzle away from substrate, and flow rate ofdispersion.

Leak testing demonstrated that silicone did not delaminate, however,grafts did see varying levels of permeability based on the amount andthickness of silicone applied. Blue dye aids in cross-sectional imagingand penetration depth. The depth varies depending on the largeintestacies of the base fabric. PVP masking agent does affectpenetration depth.

Masking Agent Deposition Examples

Various Masking Agent compositions, application methods, drying methodsand washing methods on PET graft material were explored. Testingincluded Polyvinylpyrrolidone (PVP) in water, PVP/Glycerol in water, andPVP in Glycerol as masking agents.

Methods Masking Solution A (PVP/Glycerol in Water) Preparation

PVP Masking solutions found in Table 1 and 2 were created. Each solutionwas made by mixing water and PVP in a small collection container, thenadding glycerol, if any, and dye.

TABLE 24 Solution Concentrations for Round 1 of Masking Agent DepositionTesting Sample No. Mass (g) Total Solution Mass (g) Mass of Water (g)Glycerol Mass (g) PVP Mass (g) 0% 10% 25% 40% 50% 5% 10% 25% 40% 50% 130 28.5 0.0 1.5 2 30 27.0 0.0 3.0 3 30 22.5 0.0 7.5 4 30 18.0 0.0 12.0 530 15.0 0.0 15.0 6 30 25.5 3.0 1.5 7 30 24.0 3.0 3.0 8 30 19.5 3.0 7.5 930 15.0 3.0 12.0 10 30 12.0 3.0 15.0 11 30 21.0 7.5 1.5 12 30 19.5 7.53.0 13 30 15.0 7.5 7.5 14 30 105 7.5 12.0 15 30 7.5 7.5 15.0 16 30 16.512.0 1.5 17 30 15.0 12.0 3.0 18 30 10.5 12.0 7.5 19 30 6.0 12.0 12.0 2030 3.0 12.0 15.0 21 30 13.5 15.0 1.5 22 30 12.0 15.0 3.0 23 30 7.5 15.07.5 24 30 3.0 15.0 12.0 25 30 0.0 15.0 15.0

TABLE 25 Application Methods for Round 1 of Masking Agent DepositionTesting Sample No. Sample # (refer to Test Matrix) Application Method 1A1B 1C 1D 2 1 1 6 11 16 21 2 2 7 12 17 22 3 3 8 13 18 23 4 4 9 14 19 24 55 10 15 20 25 6 26 31 36 10 46 7 27 32 37 42 47 8 28 33 38 43 48 9 29 3439 44 49 10 30 35 40 45 50 11 51 56 61 66 71 12 52 57 62 67 72 13 53 5863 68 73 14 54 59 64 69 74 15 55 60 65 70 75 16 76 81 86 91 96 17 77 8287 92 97 18 78 83 88 93 98 19 79 84 89 94 99 20 80 85 90 95 100 21 101106 111 116 121 22 102 107 112 117 122 23 103 108 113 118 123 24 104 109114 119 124 25 105 110 115 120 125

TABLE 26 Solution Concentrations for Round 2 of Masking Agent DepositionTesting Sample No. Mass (g) Total Solution Mass (g) Mass of Water (g)Glycerol Mass (g) PVP Mass (g) 0% 2% 6% 8% 10% 15% 20% 1 20 18.0 0.0 2.02 20 17.0 0.0 3.0 3 20 16.0 0.0 4.0 4 20 17.6 0.4 2.0 5 20 16.6 0.4 3.06 20 15.6 0.4 4.0 7 20 16.8 1.2 2.0 8 20 15.8 1.2 3.0 9 20 14.8 1.2 4.010 20 16.4 1.6 2.0 11 20 15.4 1.6 3.0 12 20 14.4 1.6 4.0

TABLE 27 Application Methods for Round 2 of Masking Agent DepositionTesting Sample No. Sample # (refer to Test Matrix) Application Method 1A1B 1C 1D 2 1 1 2 3 4 5 2 6 7 8 9 10 3 11 12 13 14 15 4 16 17 18 19 20 521 22 23 24 25 6 26 27 28 29 30 7 31 32 33 34 35 8 36 37 38 39 40 9 4142 43 44 45 10 46 47 48 49 50 11 51 52 53 54 55 12 56 57 58 59 60

Masking Solution B (PVP in Glycerol) Preparation

Four PVP solutions for deposition were created: (1) 25% w/w PVP inwater, (2) 50% w/w PVP in water, (3) 25% w/w PVP in glycerol and (4) 50%w/w PVP in glycerol. Each solution was made by mixing PVP with glycerolin a small collection container and heated for 10 minutes.

Masking Application Methods

For each Masking solution A and B, the following five applicationmethods were used to deposit the masking solution onto a petri dish orstraight onto a PET sample.

Application Method 1A: Coated the petri dish with 0.5 mL of solution andlaid woven PET coupon sample on top of the spread solution. The samplewas air dried.

Application Method 1B: Coated the petri dish with 0.5 mL of solution andlaid woven PET coupon sample on top of spread solution. Place depositionweight on top of the sample. The sample was air dried.

Application Method 1C: Coated the petri dish with 4 mL of solution andallowed the solution to air dry on the bottom of the dish.

Application Method 1D: Coated petri dish with 4 mL of solution andplaced in 50° C. oven to dry. Checked sample after 30 minutes in theoven and made visual observations. If all water appears to haveevaporated, sample was removed from oven and make observations describedbelow. If water had not evaporated, continued to check samples every 15minutes until samples were dry and can be removed from the oven. Whenremoved, proceed with observations described below.

Application Method 2: Placed the woven PET coupon sample in the petridish and used transfer pipet to coat the sample with 0.5 mL of solution.Dropped the solution in an evenly distributed manner to the top face ofthe sample. The sample was air dried.

Application Method 3: Immersion of woven PET crimped graft in the Masksolution.

Masking Drying Techniques

Used heat during the drying process to assess the influence of themasking agent during the drying process. Investigated the influence of(1) ambient air flow with rotation after Mask application method 3, (2)heat using an oven after Mask application method 1D, (3) irradiated heatusing heated internal mandrel after Mask application method 3, (4)forced hot air 33 mm away from the sample after Mask application method3, and (5) hot air flow through the inner diameter of the PET graftsample after Mask application method 3.

Masking agent drying techniques of forced hot air on exterior (A),heated internal mandrel (B), and hot air flow through the inner diameterof the PET graft sample.

Masking Agent Observations

After deposition of Masking solution, the samples were allowed to dry.Round 1 samples were dried for 90 hours, and Round 2 samples were driedfor 21 hours. After drying, results were documented based on thefollowing parameters:

-   1. Visual Inspection:    -   Noted any visual abnormalities in the deposition or        dissemination of the solution on the test sample. Took        photograph of each dried sample from the top and bottom of each        dried sample to note the drying pattern and wicking penetration        of each sample.-   2. Brittleness/Stiffness:    -   Manually manipulated each sample to test its brittleness. Rated        the brittleness on a 0-5 scale where 0 is indistinguishable and        5 is glazed icing. Used 18 g blunt tip needle to puncture sample        and make observations on whether the sample is sticky, tacky, or        brittle.-   3. Drying Time;    -   Note the time allowed for the sample to dry and/or time points        at which observations were made on the sample.

Results PVP/Glycerol in Water Mask

PVP concentration 10% and 15% produced the most “fabric like” samples.PVP concentration >25% were too hard and brittle without having glycerolpresent. Glycerol concentrations of 0% and 6% produced the most “fabriclike” samples. Glycerol concentration > 10% tended not to dry.

[0658] Generally, an even material distribution and 100% penetration formethod 1 (pipetting masking agent solution onto the woven PET couponsample) and method 2 (placing the woven PET coupon sample on top of themasking agent solution) was obtained; therefore, no major differencesbetween the two methods were observed. Added weight or force on a couponsample laying on top of the masking agent solution created a dryingpattern gradient, where less masking agent concentrated in the center ofthe PET sample (PET sample under the weight), and less or no maskingagent present around the edges of PET sample, where there was no addedweight.

There was no major difference in visual inspection, brittleness, ordrying time for PVP in water masking agent solutions deposited with heatwhen compared to samples of the same concentration with no heat.

PVP in Glycerol Mask

Solutions of PVP in glycerol (no water) may be used as a masking agent.Concentrations of 50% w/w PVP fully dissolves in glycerol with heat andstirring. An even masking agent distribution and controlled wick ofmasking agent was observed for 25% w/w and 50% w/w PVP in glycerolsolution. The PVP/glycerol masking agent solution tends to perform likea heavy syrup or molasses during wicking. The PVP/glycerol masking agentsolution may have a viscosity from about 2,000 to about 100,000centipoise at room temperature, more desirably a viscosity from about50,000 to about 100,000 centipoise at room temperature. Viscosity rangesof from about 5,000 to about 100,000 centipoise at room temperature;from about 10,000 to about 100,000 centipoise at room temperature; fromabout 15,000 to about 100,000 centipoise at room temperature; from about20,000 to about 100,000 centipoise at room temperature; from about25,000 to about 100,000 centipoise at room temperature; from about30,000 to about 100,000 centipoise at room temperature; from about35,000 to about 100,000 centipoise at room temperature; from about40,000 to about 100,000 centipoise at room temperature; from about50,000 to about 100,000 centipoise at room temperature; from about55,000 to about 100,000 centipoise at room temperature; from about60,000 to about 100,000 centipoise at room temperature; from about65,000 to about 100,000 centipoise at room temperature; from about70,000 to about 100,000 centipoise at room temperature; from about75,000 to about 100,000 centipoise at room temperature; from about80,000 to about 100,000 centipoise at room temperature; from about70,000 to about 90,000 centipoise at room temperature; are also useful.Masking agent solutions of 12% and 20% PVP in water had viscosities ofless than about 20 centipoise at room temperature. Glycerol was testedto have a viscosity of about 210 centipoise at room temperature. A 50%PVP in glycerol has a viscosity of greater than 80,000 centipoise atroom temperature. Surface tension (pendant drop method) was measured atabout 70 mN/m for water, about 65 mN/m for glycerol, 64 mN/m for 20% PVPin water; and about 68 mN/m for 12% PVP in water. These tests were alldone within about twenty minutes. The PVP in glycerol samples were soviscous that results could not be measured within the normal twentyminute time period. The use or application of the PVP/glycerol maskingagent solution has the advantage of controlling or minimizing wicking ofthe agent solution through the textile fibers, thereby possiblyminimizing or eliminating the need for selective removal of thePVP/glycerol masking agent solution from undesired portion of thetextile graft.

Mask Drying Techniques

TABLE 28 Fabric & Mask Weights For Drying Trials Sample No. #109 A #109B #109 C #109 D #109 A2 #110 #114 Fabric PET PET PET PET PET PET PETExtended length (cm) 24.5 25 25 24.7 24.7 23.5 34.5 Surface Area (cmsq)169 173 173 171 171 162 152 Mass fabric (mg) 2311 2370 2363 2292 23092320 2124 Mass, Wet mask (mg) 5553 5729 5417 5501 5529 5110 Mass, Drymask (mg) 2760 2817 2788 2706 2757 2720 2403 Mass Mask added (mg) 449447 425 414 448 400 279 Mass Mask/ Fabric SA (mg/cmsq) 2.65 2.59 2.462.43 2.63 2.46 1.84 % Wt gain 19.4% 18.9% 18.0% 18.1% 19.4% 17.2% 13.1%Mass (post washing) (mg) 2307

Masking agent coverage on woven PET crimped grafts varied based onmasking agent drying techniques. Ambient air dried samples (#109A and109B) looked identical and had a uniform blue color. Hot air driedsample (#109C) appeared significantly darker blue than all othersamples, although it had a paler ‘watermarked’ area adjacent to thehairdryer fan and was additionally slightly bowed, presumably due to theair force from the fan. Heated manual sample (#109D) was very uniformlycolored in the region directly adjacent to the heated mandrel. The crimphad also extended out in length in this region. In the zone above theheated mandrel the color was not as uniform and more closely resembledsamples #109A & #109B. Also, in this zone, the crimps had not elongatedin length, suggesting a differential in the drying sequence between thearea directly heated and cooler area above.

Heat via oven did not appear to improve or hinder masking drying qualityor decrease time of drying on woven PET coupon samples. However, heatincreased PVP dissolvability in water and glycerol. Temperature and timeare considerations for PVP and glycerol combinations with and withoutadded water. Increased temperatures and/or increased rates oftemperature increases may effect the final masking formulation. Ifheated too fast or too high, milky solutions may appear. Further, careshould be taken not to “burn” the glycerol. Moderate temperatures andslow temperature increases are preferred. Heating conditions, includingtemperature, time and rate, should be selected so as not to degrade themasking agent components to a point where the function of the componentsare adversely effected. Some degradation, however, for examplediscoloration, may be acceptable or even desirable. For masking agentdrying, a lid or cover over the masking agent coated woven PET couponsample increased drying time. Woven PET samples with masking agent aredesirably but not necessarily open to ambient air during drying. Thedrying techniques are not limited to PVP or polyvinylpyrrolidone, andthe drying techniques may be used on any suitable masking agentformulations, such as but not limited to, polyvinylpyrrolidone glycerol,methyl cellulose, poly(ethylene glycol), polyethylene oxide,poly(ethylene glycol) hydrogel, and combinations thereof with or withoutwater or other solvent.

Additional Observations of Mask on Woven PET crimped grafts were asfollows:

-   Ambient Dried Masking Agent With Rotation: Samples #109A and #109B    demonstrated exterior graft body a uniform color, seam appears    slightly darker blue, and color of inner surface appears identical    to outer surface.-   Hot Air Dried Mask on Exterior Surface of PET Graft: Sample #109C    demonstrate exterior graft body a darker blue color compared to    other samples and the color of inner surface appears a lighter blue    compared to the outer surface.-   Heated Mandrel Drying of Masking Agent From Interior Surface of PET    Graft: Sample #109D demonstrated a uniformed exterior graft body    color with inner and outer surfaces showing uniform depth of color.-   Hot Air Flow Drying of Masking Agent Through Interior Surface of PET    Graft: Sample #110 demonstrated a uniformed exterior color between    the peaks and valleys of the crimped graft with a paler blue top    surface compared to its bottom surface of the graft.

Visual assessment results of the inner and outer surface of each graftsample after masking agent are described below.

TABLE 29 Sample # Fabric Masking Agent Drying Method Outer and InnerSurface Different Colour Intensity Y/N Overall Uniformity of MaskCoverage Uniformity between Peak/ Valley of Crimp #109 A PET Ambient N YN #109 B PET Ambient N Y N #109 C PET Hot Air External Y Y N #109 D PETHot Mandrel N Y Y #109 A2 PET Hot Air Internal Y Y N #110 PET Hot AirInternal Y N Y #114 PET Hot Air Internal Y Y N

These results indicated that hot airflow around the outer graft surfacemay promote conglomeration of the masking agent on the outer surface(#109 C) and hot airflow through the internal lumen may promoteconglomeration of masking agent on the inner surface (#109A2, #110,#114).

There was notable overall uniformity on graft sample #109A2 on bothoutside and inside surfaces, however this graft showed some variationbetween peaks and valleys of the crimps.

Graft sample #110, however, demonstrated some variation between the topand bottom faces, yet both faces showed considerable uniformity betweenpeaks and valleys of the crimps.

For graft sample #109A2 (A) and #110 (B) after masking agent drying,there were inconsistencies between the funnelling of heated air throughthe inside of grafts #109A2, #110, #114 and this may have resulted insignificant variation in the resultant airflow acting on the innersurface.

Mask Washing Process

A blue water-soluble dye was added to the masking agent solution usedfor all samples in order to provide a visual indication of both locationof masking agent and concentration of masking agent on the dried graft.Sample #109 A was applied with masking agent in an identical manner to#109 B and then subjected to a 90C ‘Cotton Wash’ to assess the viabilityof removal of the blue dye from the woven PET graft. It was unclear ifthe dye stained only the PVP Mask or if it can permanently stain the PETyarn and therefore dye cannot be fully removed during the wash cycle.

The mass of the graft was measured at each stage with the graft mass,post-wash returning to 2307 mg vs 2311 mg pre-mask application. Thisindicated that all PVP mask had been removed by the wash process,however after washing and drying #109A appeared to have a very pale bluecolor, as compared below alongside a fresh graft sample. The presence ofthis blue tone suggests that traces of blue dye can stain the PET graftpermanently and is therefore may not be a good tool by itself forassessing or confirming the presence of PVP masking agent in thefinished sealed graft post-washing.

Observations and Conclusions

For PVP/Glycerol in water masks: Masking agent concentrations were most“fabric like” with PVP concentration <25% w/w (most preferred 10-15%w/w) and glycerol concentrations < 10% w/w (most preferred 0-6% w/w).Glycerol concentrations > 10% w/w did not completely dry. PVPconcentrations >25% w/w (at low glycerol concentrations) seemed hard andbrittle. Heat increased the ability for PVP to dissolve in water.

For PVP in glycerol (no water) masks: PVP/glycerol may be used as amasking agent without any added water. Concentrations of 50% w/w PVPwere fully dissolved in glycerol with heat and stirring. An even maskingagent distribution during application and controlled wicking of makingagent was observed while using 50% w/w PVP in glycerol. The PVP/glycerolmasking agent solution tended to perform like molasses during wicking,whereas the PVP/glycerol/water masking agent solution tended to performlike water during wicking. Excess masking agent on the outside of thegraft can be removed or washed off with water.

PVP/Glycerol without added water may contain trace amounts of moisturefrom exposure, for example, from atmospheric conditions. As used hereinPVP/Glycerol without added water may be substantially free of water, forexample less than 0.5 weight percent water, more desirably less than 0.1weight percent water, including less that 0.01 weight percent water. ForPVP/Glycerol formulations with purposely added water, it is believedthat the added water may wick to some degree through the fibers of theyarn. Having PVP/Glycerol without added water does not present such awicking problem.

Masking agent solutions of PEG in Water were also prepared. Inparticular, nine PEG solutions for deposition were created as follows:(1) 10% w/w PEG (MW 600) in water, (2) 25% w/w PEG (MW 600) in water,(3) 50% w/w PEG (MW 600) in water, (4) 10% w/w PEG (MW 4000) in water,(5) 25% w/w PEG (MW 4000) in water, (6) 50% w/w PEG (MW 4000) in water,(7) 10% w/w PEG (MW 8000) in water, (8) 25% w/w PEG (MW 8000) in waterand (9) 50% w/w PEG (MW 8000) in water. Each solution was made by mixingPEG with water in a small collection container. The PEG masking samplestested at 10% w/w concentration did not dry completely. PEG (MW 600)masking samples remained liquid at all concentrations tested. PEG (MW4000, MW 8000) masking samples were almost completely solid at 50%. PEGmasking samples at 50% w/w concentration did not completely dissolve.PEG (MW 600, 4000, and 8000) dissolved into water <50% w/w concentrationand demonstrated to be a good potential polymer for the masking agent.PEG MW 600 remained liquid (i.e. never fully dried) for allconcentrations (10%, 25%, 50%), PEG MW 4000 and 8000 were essentially asolid at 50%. PEG at 50% concentration did not completely dissolve, butPEG masking agent solutions at 45% w/w or less will likely dissolve. AllPEG masking solutions cracked after the drying process. PEG samplescrack similar to “desert cracks” (large, protruded cracks), whereas PVPsamples crack similar to “window glass cracks” (small, micro channelcracking). The use of a plasticizer, such as glycerol may eliminate orminimize the presence of cracks.

Removing excess masking agent from the outside of the graft surface maybe accomplished by subjecting the outside of the graft to a wash or mistof water or other wash solvent. The step of removing excess maskingagent may include having the graft disposed over a mandrel, such asmandrel 20. As described herein, the mandrel 20 may offer a solidexterior surface for which may act as a barrier from water washing themasking agent from the interior portions of the graft. Alternatively, orin addition to, mandrel 20 may have holes or perforations through whicha medium, such as air or nitrogen, may flow to act as a further barrieragainst water from washing the masking agent from the interior portionof the graft.

Masking Agent Application Methods: No masking agent depositiondifferences between pipetting masking agent directly onto the graft andgraft placed on top of masking agent solution. Added weight (a nickel)dispersed the wicking of the masking agent and created an obviousgradient in the masking agent drying pattern. More masking agent waspresent on the graft where weight was not applied. The masking agentmass applied per unit surface area for PET samples was relativelyconsistent which indicates that the immersion dipping process isreasonably consistent. An even masking agent distribution and 100%penetration for all application methods: (a) Graft material placed ontop of masking agent solution for wicking, (b) pipet masking agentsolution on top of the graft material and (c) immersion dipping ofgraft.

Mask Drying Methods: Oven drying did not affect masking agent dryingcompared to ambient air. Covered drying at room temperature or usingheat increases masking agent drying time. Warm airflow around the graftsurface appeared to have a significant effect on the masking agentdrying mechanism and can be used to influence the final location andconglomeration of masking agent. The application of hot airflow throughthe inside of the graft appeared to promote the conglomeration ofmasking agent on the inner surface which provides an attractive processfeature in ensuring the inner graft surface is free of siliconedispersion whilst minimizing masking agent presence on the outer surfacethat could reduce Silicone to fabric adhesion levels. The horizontalrotation of the graft during the masking agent drying process remained avaluable process aid to provide a perfectly straight (co-axial) graftfor subsequent spray coating process, otherwise the graft dries in a bowshape. The horizontal rotation during drying process may be includedwhen considering methods to apply warm airflow.

Mask Washing Process: Blue dye added to masking agent solution providesa useful indication of both the dried masking agent location andconcentration/conglomeration, however the dye may stain the PET graftpermanently and is therefore may not a good tool for assessing orconfirming the presence of PVP Mask in the finished sealed graftpost-washing.

The PET graft edges and seam appeared to hold or absorb differentamounts of Mask when compared to the main body of the graft due to thelocalized differences in weave structure and density.

Additional Testing on Textile Grafts

Graft Tested: ATEX Technologies Polyester Vascular Graft; 14 mmDiameter, 28.5 crimps per inch (CPI)

Equipment and Materials:

-   I. 14 mm crimped polyester fabric (Atex Technologies)-   II. Hothouse (HH) Spray Rig-   III. Bespoke Mandrels-   IV. Polyvinylpyrrolidone (PVP) Powder-   V. NuSil MED-6606 RTV Silicone-   VI N-Heptane-   VII. Easy Composites Royal Blue Pigment-   VIII. De-ionized water-   IX. Magnetic Stirrer (VFT Asset ID :22)-   X. Plastic Beakers-   XI. Cable ties-   XII. Single edge Razor Blades-   XIII. Scales (VFT Asset ID :84)

Coating Variables

The formulation of the masking agent and sealant composition arevariables for consideration in controlling the effectiveness of thecoating for the graft. Other factors that have been identified as beingimportant include, but not limited to, masking agent drying method. Thedrying method was not varied in the below examples, and all grafts weredried in ambient air whilst being rotated.

In examples described earlier herein above, silicone was brushed on toensure a large coverage was achieved, this was to ensure there wasenough silicone on the graft to show penetration but also a goodcoverage to ensure delamination was demonstrated. There was also bluedye added to the silicone to help assess the penetration visually. Thebelow examples were carried out on two sets of 26 samples. The first sethad blue dye added to the silicone and the coverage was set at 14mg/cm², these samples were used to assess penetration. The second sethad silicone with no dye and the coverage was set at 20 mg/cm², thesesamples were used to test adhesion.

In addition to the above-described 52 samples, there was also be twocontrol grafts C1 and C2. These were coated with silicone only with nomask application, C1 had the blue dye added to the silicone also.

Coating Variable Ranges

The following values were used for the testing:

-   PVP Concentration in DI water: 1%, 2%, 4%, 6%, 8%, 10%, 12% 15%,    17%, and 20%.-   Silicone dispersion concentration: 15% and 30%-   Glycerol Concentrations used on each PVP concentrations: 5%, 10%,    and 15%. These concentrations are percentage of Glycerol to PVP    concentration.

The various samples prepared are shown in Table 30 below with targetmasking agent and sealant components as listed below.

TABLE 30 Test Matrix Sample ID HH Sample ID PVP Concentration (%)Glycerol Cone. (% of PVP) Silicone Conc. (%) Blue Dye No Dye Blue Dye NoDye 1 2 4 6 8 10 12 15 17 20 5 10 15 15 30 C1 C2 136A 136B X 1 27 137 A137B X X 2 28 138A 138B X X 3 29 139A 139B X X 4 30 142A 142B X X 5 31141A 141B X X 6 32 140A 140B X X 7 33 143A 143B X X 8 34 144A 144B X X 935 145A 145B X X 10 36 146A 146B X X 11 37 147A 147B X X X 12 38 148A148B X X X 13 39 149A 149B X X X 14 40 150A 150B X X X 15 41 151A 151B XX X 16 42 152A 152B X X X 17 43 153A 153B X X X 18 44 154A 154B X X X 1945 155A 155B X X X 20 46 156A 156B X X X 21 47 157A 157B X X X 22 48158A 158B X X X 23 49 159A 159B X X X 24 50 160A 160B X X X 25 51 161A161B X X X 26 52 162A 162B X X X Note: Samples C1 and 1-26 had acoverage of about 14 mg/cm². Samples C2 and 27-52 had a coverage ofabout 20 mg/cm².

Preparation Method Sample Preparation

Each sample was removed from the store and assigned a HH sample IDnumber. Each sample was to be made up of a section of graft. Firstly,the graft was cut to length. The graft was fully stretched removing thecrimp, and a section of 225 mm length was cut with a single edge razorblade, once cut the end was cauterized to prevent fraying. The samplewas clean and free of any debris, if it is not then it is to bediscarded or washed and allowed to dry. Weighed the cut graft and notedthe weight on the test sheet. Marked each sample with the HH sample IDnumber using black ink.

Masking Agent Preparation

To prepare the masking agent formulation, the quantities of thecomponents needed were calculated. This was done by calculating thepercentage of each based on the test matrix. The amount of eachcomponent was noted on the test sheet for each sample. The followingsteps were followed to make the masking agent formulation.

Placed the correct amount of de-ionized water into a 100 ml plasticbeaker.

Placed magnetic stirrer in the water and place the beaker on themagnetic stirrer.

Turned the magnetic stirrer on at a speed of approximately 400 RPM atroom temperature.

Measured the correct weight of PVP and glycerol onto weighing boats.

Added the PVP and Glycerol to the water.

Stirred till there is no solute visible.

Masking Agent Application

After the mask was fully prepared, the graft was coated. This was doneby immersing the graft within the masking agent solution and agitatingthe graft by gloved hands, so it was fully coated inside and out.

Once the graft was saturated, the excess masking agent solution wasremoved by running the graft between a thumb and index finger. Next thegraft was attached to a mandrel, this was done using cable ties. Cabletied one end of the graft to the mandrel, extended the graft to 60% ofits overall extended length (135 mm), and cable tied the other end ofthe graft to the mandrel. The mandrel was then be placed horizontally onthe rotisserie and allowed to air dry for 12 hours. Once dry, weighedthe masked graft and noted the weight on the test sheet.

Sealant Preparation

The sealant came supplied as a 30% solid content. For the samplesrequiring the 30% the sealant was used straight from the container. Forthe remainder of the samples the sealant was diluted. The correct amountof n-Heptane was added to reduce that solid content to 15%.

To allow for visualization of where the sealant is on grafts C1 and1-26, blue dye was added to the silicone dispersion. The blue dye was tobe added so that it amounted to 5% concentration with the solid content,i.e. at 15% solid content 15 g of dispersion has 2.25 g of solid contenttherefore you would add 0.11 g of dye.

The appropriate amount of silicone was measured out to give the targetcoverage of either 14 mg/cm² or 20 mg/cm² coverage, and it was loadedinto one of the disposable syringe barrels. This amount accounted for a25% loss when spraying, therefore the actual target spray levels were17.5 mg/cm² and 25 mg/cm² respectively.

Sealant Application

The spray head was flushed with n-Heptane to ensure correct flow. Themandrel with the graft was then mounted in the spray rig. The spray rigwas set up to spray the entire length of graft. The syringe barrel withsilicone was mounted onto the spray head. The graft was rotated at 150RPM, and the rate of traverse was set to 20 mm/s. The spray head wasstarted and traversed over the entire length of the graft, once itreached the opposite end the spray head was stopped and allowed toreturn to the start of the graft. The solvent was allowed to flash offbefore making another pass, the time taken for the solvent to flash offincreased with the amount applied. After the first pass a time of 10seconds was waited, after each additional pass another 10 seconds wasadded to the wait time up to a maximum of 40 seconds between each pass.This continued till there was no dispersion left in the syringe barrelor there was an insufficient amount to make another full pass. Once thegraft was removed from the spray rig the spray head was flushed withn-Heptane again.

After application the graft was transferred to the rotisserie for aperiod of 12 hours then transferred to a stationary mount and allowed toair dry for a further 60 hours. Once dry, the sealed graft was weighedand the weight recorded.

Masking Agent Removal

Once the graft was fully dried the mask was removed. This was done bywashing the grafts in a washing machine on a “cotton cycle” at 90° C.(with no detergent). This caused the PVP to be dissolved in the waterand removed, and also the high temperatures aided the curing of thesilicone. When the wash was complete, the graft was hung up to air dry.Once the masking agent was removed and the graft was dry, the finishedgraft weight was recorded.

Testing Method Silicone Adherence

Silicone adherence may be difficult to measure in that the force to peelthe silicone and the force to break the very thin silicone are bothextremely low. Therefore, one method to demonstrate if the graft hasgood adherence is to pressurize the sample and see if there are anysigns of the silicone losing its bond from the graft. The pressure wasto be increased slowly to a maximum pressure of 600 mmHg. The adherencewas to be noted as follows:

-   0 - Silicone is well adhered to graft and showing no signs of    failure.-   1 - Graft reached the maximum pressure, but the leak rate has    visibly increased.-   2 - Silicone coating has started to fail, showing jets of water    coming from the graft.-   3 - Silicone coating has failed, and a bubble has appeared on the    surface.

The adherence test was to be completed for all samples.

Penetration Depth

The effectiveness of the masking agent was determined by how far thesilicone wicked through the fabric. Ideally the silicone will sit on theoutside surface of the graft and not penetrate the graft structure. Ifthe masking agent was not effective, then the silicone may be visiblewithin the fabric and on the inside edge. To visualize this, each graftwas cut lengthways so that a cross section could be examined under highmagnification. Particular attention was given to where this cut was madeas the penetration may vary between the main body of the graft and atthe seams. For comparative purposes a cross section was made at eachposition and the penetration noted at each.

As the depth cannot be measured the penetration was noted as follows:

-   0 – Silicone only visible on the outer surface of the graft.-   1 – Silicone is visible between fibers of the graft but only up to    50% of the thickness.-   2 – Silicone is visible penetrating to the inside surface.-   3 – Silicone visible everywhere, the entire graft structure is blue.

The penetration depth test was completed for grafts C1 and 1-26 only.

Results & Analysis

Table 31 below lists the measured weights of the masking agent andsealant formulations after the noted processing steps. Masking agent andsealant coverages are noted in the table.

TABLE 31 Weight Summary Sample No. HH ID Initial (mg) After Masking andDrying (mg) After Sealant and Curing (mg) After Washing and Drying (mg)Mask Coverage (mg/cm²) Sealant Coverage (mg/cm²) C1 136A 1459 1459 30453041 0.000 15.2 1 137A 1440 1451 2927 2918 0.107 14.4 2 138A 1469 14952867 2839 0.246 13.0 3 139A 1475 1532 2815 2756 0.540 12.1 4 142A 14401590 3071 2915 1.439 14.2 5 141A 1187 1307 2584 2468 1.428 15.2 6 140A1487 1578 3085 2993 0.855 14.1 7 143A 1575 1799 3214 2995 2.005 12.7 8144A 1564 1867 3279 2973 2.681 12.5 9 145A 1534 1862 3161 2835 3.04412.1 10 146A 1318 1645 3000 2677 3.474 14.4 11 147A 1619 1690 3139 30740.621 12.7 12 148A 1485 1557 2911 2841 0.679 12.8 13 149A 1311 1422 26052493 1.190 12.7 14 150A 1580 1723 3043 2899 1.270 11.7 15 151A 1588 18102870 2650 1.979 9.5 16 152A 1561 1805 3078 2834 2.219 11.6 17 153A 15101901 3011 2625 3.599 10.3 18 154A 1558 2029 3205 2745 4.216 10.6 19 155A1374 1426 2405 2350 0.537 10.1 20 156A 1342 1395 2948 2901 0.560 16.5 21157A 1333 1452 2706 2589 1.247 13.2 22 158A 1393 1503 2962 2852 1.10714.7 23 159A 1390 1600 2844 2633 2.132 12.6 24 160A 1344 1525 3023 28421.905 15.8 25 161A 1398 1776 3273 2904 3.737 14.9 26 162A 1344 1722 32312857 3.979 15.9 C2 136B 1520 1520 3860 3857 0.000 21.6 27 137B 1432 14443474 3470 0.117 19.8 28 138B 1396 1428 3460 3439 0.321 20.5 29 139B 14931556 3625 3573 0.602 19.9 30 142B 1430 1582 3846 3711 1.509 22.6 31 141B1428 1543 3695 3604 1.147 21.7 32 140B 1468 1570 3758 3571 1.004 20.7 33143B 1533 1723 3758 3571 1.714 18.4 34 144B 1539 1868 4044 3720 2.99219.8 35 145B 1523 1818 4034 3742 2.749 20.7 36 146B 1350 1704 3743 33933.709 21.4 37 147B 1459 1519 3649 3595 0.581 20.7 38 148B 1578 1636 36183547 0.517 17.6 39 149B 1266 1366 3074 2966 1.109 18.9 40 150B 1495 16383172 3030 1.344 14.4 41 151B 1556 1806 3289 3040 2.265 13.4 42 152B 14821700 3108 2890 2.065 13.3 43 153B 1560 2014 3509 3068 4.096 13.6 44 154B1578 2132 4480 3944 4.979 21.3 45 155B 1263 1316 3473 3427 0.594 24.2 46156B 1321 1375 3489 3434 0.571 22.3 47 157B 1324 1454 3681 3551 1.36823.4 48 158B 1286 1407 3524 3407 1.316 23.1 49 159B 1287 1487 3644 34472.155 23.3 50 160B 1294 1488 3508 3317 2.052 21.4 51 161B 1270 1675 38023409 4.470 23.6 52 162B 1305 1684 3781 3406 4.065 22.5

The above-described penetration grading of the sealant is listed inTable 32 below.

TABLE 32 Penetration Sample No. HH ID PVP (g) Glycerol as % of PVPPolymer Concentration (%) Penetration Grading C1 136A 0 0 15 3 1 137A 10 15 3 2 138A 2 0 15 3 3 139A 4 0 15 3 4 142A 6 0 15 3 5 141A 8 0 15 3 6140A 10 0 15 3 7 143A 12 0 15 3 8 144A 15 0 15 3 9 145A 17 0 15 3 10146A 20 0 15 2 11 147A 4 5 15 3 12 148A 4 15 15 2 13 149A 8 5 15 3 14150A 8 15 15 3 15 151A 12 5 15 2 16 152A 12 15 15 2 17 153A 20 5 15 2 18154A 20 15 15 2 19 155A 4 10 15 2 20 156A 4 10 30 2 21 157A 8 10 15 2 22158A 8 10 30 2 23 159A 12 10 15 1 24 160A 12 10 30 2 25 161A 20 10 15 226 162A 20 10 30 1

Permeability data at 120 mmHg and leakage data are 600 mmHg are shownbelow in Table 33.

TABLE 33 Adhesion Sample No. HH ID PVP (g) Glycerol as % of PVP MeasuredLeakage (ml/min) @ 120 mmHg Measured Leakage (ml/min) @ 600 mmHgPermeability at 120 mmHg (ml/min/cm²) Adhesion Grading Scale 0-3 C1 136A0 0 1 137A 1 0 2 138A 2 0 3 139A 4 0 4 140A 6 0 5 141A 8 0 6 142A 10 0 7143A 12 0 0 4.8 0 1 8 144A 15 0 2.8 27 0.05 1 9 145A 17 0 2.8 21 0.05 110 146A 20 0 7 43 0.14 1 11 147A 4 5 0 0 0 0 12 148A 4 15 0 0 0 0 13149A 8 5 0 0 0 0 14 150A 8 15 0 4.6 0 1 15 151A 12 5 0 8.8 0 1 16 152A12 15 2.5 16 0.05 1 17 153A 20 5 15 100 0.32 2 18 154A 20 15 Delaminatedcircumferentially Delaminated circumferentially 0 3 19 155A 4 10 0 0 0 020 156A 4 10 0 0 0 0 21 157A 8 10 0 Delaminated at the seam 0 3 22 158A8 10 0 Delaminated at the seam 0 3 23 159A 12 10 0 Delaminated at theseam 0 24 160A 12 10 0 Delaminated at the seam 0 3 25 161A 20 10Delaminated Delaminated 0 3 26 162A 20 10 Delaminated Delaminated 0 3 C2136B 0 0 0 0 0 0 27 137B 1 0 0 0 0 0 28 138B 2 0 0 0 0 0 29 139B 4 0 0 00 0 30 142B 6 0 0 0 0 0 31 141B 8 0 0 Delaminated at the seam 0 3 32140B 10 0 0 Delaminated at the seam 0 3 33 143B 12 0 0 Delaminated atthe seam 0 3 34 144B 15 0 Delaminated circumferentially Delaminatedcircumferentially 0 3 35 145B 17 0 0 Delaminated circumferentially 3 36146B 20 0 Delaminated circumferentially Delaminated circumferentially 03 37 147B 4 5 0 0 0 0 38 148B 4 15 0.5 5.2 0.01 1 39 149B 8 5 0 0 0 0 40150B 8 15 0 0 0 0 41 151B 12 5 0 Delaminated 0 3 42 152B 12 15 0Delaminated at the seam 0 3 43 153B 20 5 Delaminated circumferentiallyDelaminated 0 3 44 154B 20 15 Delaminated Delaminated 0 3 45 155B 4 10 00 0 0 46 156B 4 10 0 0 0 0 47 157B 8 10 0 0 0 0 48 158B 8 10 0 0 0 0 49159B 12 10 0 Delaminated at the seam 0 3 50 160B 12 10 0 Delaminated atthe seam 0 3 51 161B 20 10 Delaminated Delaminated 0 3 52 162B 20 10Delaminated Delaminated 0 3

Glycerol Concentration

All samples in the above tables were considered for penetration andadhesion respectively, for each glycerol concentration and averaged. Theaddition of glycerol generally appeared to decrease penetration on 4-12%PVP, but had little effect in higher concentrations of 20%. With respectto adhesion the addition of glycerol appeared to have less effect atlower concentrations of PVP and tended to decrease adhesion at higherPVP concentrations.

Silicone Dispersion Concentration

Looking at silicone concentrations showed no real significant differencebetween 15% or 30%. The penetration grading was so close when gradingthat they could be assumed to be the same for each PVP concentration.Therefore, there was no real difference in either case. One notabledifference when spraying was that, the 30% silicone dispersion requiredmuch less time between coats and required less dispersion to be put onthe graft, therefore the total time to coat these grafts was reduced.

Table 34 lists forces-to-extend values for the various samples tested.

TABLE 34 Handling HH Sample ID PVP Mask Conc. (%) Glycerol Cone. (% ofPVP) Polymer Cone. (%) Silicone Coverage (mg/cm²) Force to Extend(Normalized with Circumference) (N/mm) 136(A) 0 0 15 15.24111 0.052137(A) 1 0 15 14.4225 0.046 138(A) 2 0 15 12.97871 0.041 139(A) 4 0 1512.13556 0.029 140(A) 10 0 15 14.1503 0.025 141(A) 8 0 15 15.24888 0.031142(A) 6 0 15 14.14919 0.035 143(A) 12 0 15 12.71091 0.024 144(A) 15 015 12.46522 0.019 145(A) 17 0 15 12.0735 0.020 146(A) 20 0 15 14.438690.023 147(A) 4 5 15 12.72365 0.038 148(A) 4 15 15 12.79277 0.037 149(A)8 5 15 12.67663 0.029 150(A) 8 15 15 11.71459 0.026 151(A) 12 5 159.46905 0.019 152(A) 12 15 15 11.57739 0.023 153(A) 20 5 15 10.263610.015 154(A) 20 15 15 10.62525 0.014 155(A) 4 10 15 10.0867 0.029 156(A)4 10 30 16.48655 0.032 157(A) 8 10 15 13.15988 0.029 158(A) 8 10 3014.67807 0.027 159(A) 12 10 15 12.61668 0.020 160(A) 12 10 30 15.768130.023 161(A) 20 10 15 14.88741 0.020 162(A) 20 10 30 15.92602 0.020

Handling was assessed using the same procedure as described hereinabove. The above table shows average force values against PVPconcentrations. PVP concentrations of above 10% gave better handlingthan the reference sample describe earlier herein. This supports theconclusions that the higher PVP concentrations lower penetration intoyarn bundles which results in more favorable handling characteristics.

Also, to be noted from the results was that although generally a highersilicone coverage resulted in poorer handling, it was not the onlyfactor. For example, sample 162(A) had a high coverage of 15.9 mg/cm²,but had a better handling result than the reference sample.Alternatively, sample 147(A) had a lower coverage of 12.7 mg/cm² and hadworse handling than the reference sample. This suggests that it is infact penetration that more greatly impacts handling rather than coverageas sample 162(A) had a penetration score of 1 compared to sample 147(A)that had a penetration score of 3. The increase in silicone coverage mayhave a smaller impact on handling than the change in PVP concentrations.

Seam Delamination

During the adhesion testing, seam delamination was observed at higherpressures. The bubbles formed were diametrically opposed, running alongthe seam. The fabric was examined under microscope and the seam regionwas visibly more tightly weaved compared to the main body of the graft.Therefore, it was only logical to ask if the delamination at the seam issolely due to the protocol followed and should be considered a “fail”,or the tight seam hinders the silicone to adhere.

In the initial analysis, any type of delamination was given an adhesiongrade 3. However, after consideration, it was decided to examine thedata again. The delamination at the seam was, this time, not considereda grade 3. So, this section will compare two cases: (1) seamdelamination is considered as a fail criterion, (2) seam delamination isnot considered as a fail criterion.

Seam delamination was observed in the 8-12 % range. An improvement ofadhesion is evident in case 2, which only reinforces previousconclusions that the seam can have a negative effect on siliconeadhesion. Similarly, a comparison between silicone content and adhesionin the two cases in question shows there is increased adhesion in case2, specifically for 30% silicone. In case 1, 15% silicone content yieldsmore favorable results, while in case 2, this is true for 30% siliconecontent.

Conclusions

A consistent silicone coverage was achieved with a spray rig with asmall standard deviation of the spraying results. The use of blue dyedsilicone for penetration assessment and clear for adhesion assessmentappeared to work very well. A repeatable mask coverage is achievablewith standard deviation at 10% of the average value. The fabric has alarge impact on the success of the coating, in particular the presenceof a seam. Adhesion results of seamed grafts were not as comparable toseamless grafts, but if the grafts had not delaminated at the seams, theresults would have been much closer. Both glycerol concentration andsilicone dispersion concentration appeared to have less effect thanprevious, this may be a result of the points above. Glycerol appears tolower penetration at low PVP concentrations and has less effect athigher PVP concentrations. Glycerol has less effect on adhesion at lowerPVP concentrations and at higher PVP concentrations lowers adhesion.Silicone dispersion had no clear influence on the success of the coatingwith respect to adhesion and penetration. Grafts coated with the 30%dispersion appeared to have a more uniform coating of silicone. Coatingtime was greatly reduced when using 30% dispersion compared to 15%. Thereduced coating time with 30% dispersion lead to less blockages withinthe spray head. Handling was more sensitive to penetration rather thansilicone coverage.

The use of glycerol is, however, not limited to just as an additive tothe masking agent formulation. Glycerol may be applied to the graft, inparticular, to select portions of the graft, prior to the application ofthe masking agent. Such added glycerol may act as a plasticizer to themasking agent applied at the portion of the graft having the addedglycerol. Portions of grafts that have, for example, differentdensities, such as but not limited to seams, may benefit with theapplication of glycerol prior to the application of the masking agent.

Handling comparable to reference sample 64B was achievable with PVPconcentrations greater than 10%. Handling is also effected by theuniformity of the silicone coating from peaks to valleys. Excluding seamdelamination from the fail criteria, yields more positive results for arange of concentrations that were previously thought to be favorable.

In summary, adhesion was higher in 8-12% PVP concentration. Highersilicone content offered better adhesion.

Visual Indicators

As described herein, the masking agent formulation and/or the sealantcomposition may contain a colorant or dye. The colorant or dye may beany useful and medically suitable, e.g., biocompatible, dye. The dye maybe biostable or may degrade over time after implantation in the body.Any useful color, such as blue, green, red, orange, and the like may beused. Further, the masking agent and/or sealant compositions may have aninherent color or tint which is distinguishable from medical gradetextile yarns.

Such a visually distinguishable masking agent and/or sealantcompositions may be useful with the methods and products of the presentinvention. For example, visually distinguishable masking agent may beuseful in ascertaining that the interior portions of a graft havesufficient masking agent coverage to inhibit sealant migration thereto.Such a visually distinguishable masking agent may also be useful inascertaining that the exterior portions of the graft are free orsubstantially free of masking agent coverage so that the sealantcomposition may adequately cover the exterior of the graft, includingsecurably covering the exterior of the graft to achieve substantiallyfluid impermeable sealing.

A visually distinguishable sealant composition may be useful inascertaining that exterior portions of the grant have sealant coverage.For example, a practitioner could differentiate between a non-sealedgraft having the color, such as white, typical of medical textiles and asealed graft of the present invention having a non-white color, such asblue, green, etc. Thus, a practitioner could readily distinguish betweena permeable non-sealed graft and a substantially impermeable sealedgraft of the present invention.

If colorants or dyes are added to the masking agent and/or sealantcompositions, then the levels of the colorants or dyes should not be ata level which interferes with the intended purpose of the masking agentand/or sealant compositions.

Homogeneous Sealant Application and Coverage

Tests were performed to investigate the theory that the addition of themask allows a thinner coating of silicone to be applied to the graftbefore a sufficient seal is obtained. This was done by applying siliconecoatings at various target coverage levels and carrying out whole graftporosity on them to determine the level of seal. While the tests wereperformed with particular sealing and masking agents, any of theabove-described sealing and masking agents may suitably be used.

Tests were carried out on ATEX crimped and non-crimped polyester fabricas described below:

-   ATEX Technologies Polyester Vascular Graft – 14 mm Dia. – 28.5 CPI-   ATEX Technologies Polyester Vascular Graft – 14 mm Dia. – Uncrimped

Equipment and Materials:

-   14 mm crimped polyester fabric (Atex Technologies)-   14 mm non-crimped polyester fabric (ATEX Technologies)-   Polyvinylpyrrolidone (PVP) Powder-   De-ionised water-   MED6-6606 Silicone Dispersion-   n-Heptane-   Easy composite royal blue pigment-   Mandrels and mounts-   Hothouse (HH) Rotisserie-   Magnetic Stirrer-   Measuring jug-   Scales-   Blasting Cabinet

Coating Variables

The presence of the masking agent has been shown to limit thepenetration of the silicone through the graft structure as describedearlier herein. The masking agent also appears to cause the siliconeleft on the surface to be more homogenous, resulting in a thinnercoverage required to get a complete seal than with bare or non-maskedfabric. Therefore, a range of silicone coverages was tested on a controlof bare fabric and on grafts prepared with an optimised mask process.This was carried out on both crimped and non-crimped fabric to determineany differences.

Control Graft Samples Preparation

Woven graft samples were coated with a 30% silicone dispersion inheptane (no mask). The silicone coverages targeted were 4, 6, 8, 10,and12 mg/cm².

Optimized Mask Samples Preparation

Woven graft samples were prepared with mask (20% w/w PVP and 5% w/wGlycerol (to PVP) in water) applied using an immersion method. Once themask was dried via rotation at room temperature, excess mask on theouter graft surface was soda blasted via sodium bicarbonate at 25-30psig, while rotating the graft at 100 RPM. Blast particles were removedusing a vacuum and heptane wash, then dried. Masked coated graft sampleswere sprayed coated with a 30% silicone/heptane dispersion. The siliconecoverages targeted were 4, 6, 8, 10, 12 mg/cm².

Silicone Dispersion

Flushed spray head with n-heptane. Mounted graft and silicone/heptanedispersion syringe barrel in the spray rig. Sprayed silicone onto graftduring rotation at 150 RPM and traverse 20 mm/s. Sprayed whole length ofgraft, then allowed heptane to flash off before making another pass(about 10 seconds). Repeated until no dispersion left in the syringebarrel. Dried for 6 hours with rotation and 66 hours stationary. Graftsample were dried if there was no vinegar odour.

Removed mask via water wash at 90° C. Warm water wash dissolved the PVPfor removal and aided the silicone curing. Dried via ambient air.

The most desirable mask process used a 20% PVP masking agent with 5%Glycerol (to PVP). The masking agent once dried was abraded with sodiumbicarbonate soda at pressure of 25 to 30 psig. Details of the abradingprocess are described previously herein. The grafts were also coatedwith a 30% silicone dispersion. The decision for this process was takenfrom results presented earlier herein, where a 20% PVP masking agentperformed well after abrasion and that at higher PVP concentrations alower glycerol concentration was beneficial.

Details for preparing (1) control graft samples and (2) masked graftsamples for silicone coverage trials are listed below in Table 35.

TABLE 35 Test Matrix Sample ID HH Sample ID Controls Optimised MaskSilicone Coverage (mg/cm²) Silicone Coverage (mg/cm²) 4 6 8 10 12 4 6 810 12 Crimped 1 220 X 2 221 X 3 222 X 4 223 X 5 224 X 6 225 X 7 226 X 8227 X 9 228 X 10 229 X Un-crimped 11 230 X 12 231 X 13 232 X 14 233 X 15234 X 16 235 X 17 236 X 18 237 X 19 238 X 20 239 X

Method

Sample preparation: Each sample was removed from the store and assigneda HH sample ID number. Each sample was to be made up of half a graft.Firstly, the graft was cut in half. The graft was fully stretchedremoving the crimp, if applicable, and cut at the midpoint with a singleedge razor blade, once cut the end was cauterized to prevent fraying.The samples were clean and free of any debris. The weights of Cut graftsections were recorded. Each sample was marked with sample IDs.

The control samples were put to the side ready for mounting.

Masking Agent Preparation

To aid the abrasion of the mask it was beneficial to have some sort ofdye in the masking agent. The reason for this is that it gives a visualaid into how much is being removed.

To prepare the masking agent formulation, the following steps werefollowed:

-   Placed 200 ml of de-ionised water into a 100 ml plastic beaker.-   Placed Magnetic stirrer in the water and place the beaker on the    magnetic stirrer.-   Turned the magnetic stirrer on at a speed of approx. 400 RPM at room    temperature.-   Measured 40 g of PVP and 4 g of glycerol onto weighing boats.-   Added the PVP and Glycerol to the water.-   Added 2 drops of yellow dye.-   Stirred till there was no solute visible.

Masking Agent Application and Drying

After the mask was fully prepared, the graft was coated. This was doneby immersing the graft within the masking agent solution and agitatingthe graft by gloved hands, so it is fully coated inside and out.

Once the graft was saturated, the excess mask solution was removed byrunning the graft between a thumb and index finger. Next the graft wasto be attached to a mandrel, this was done using cable ties. Cable tiedone end of the graft to the mandrel, in the case of the crimped grafts,extended the graft to 60% of its overall extended length, and cable tiedthe other end of the graft to the mandrel. The mandrel was then beplaced horizontally on the rotisserie and allowed to air dry for 12hours. Once dried, the weight of the masked graft was recorded.

The dry masked graft were then mounted on a solid mandrel and cable tiedin place. The mandrel was mounted within the blasting cabinet attachedto the rotating chuck and set to a speed of approximately 100 RPM. Thesoda blaster (or sodium bicarbonate abrader) was filled with bicarbonateof soda and set to a pressure of 25 to 30 psig. The graft was then berotated and the soda blast gun traversed over the surface at asufficient speed to not miss any of the surface, once one full pass wasmade, repeated the traverse for a second time. It should be noted thatthe pressure of the abrader for the present invention may be as high as50 psig, which in some cases will affect the integrity of the underlyingtextile but may be acceptable depending on the remaining structuralintegrity, of the textile.

After the blasted grafts have been ablated, they were washed to removeany particulates of mask or bicarbonate of soda that was still on thesurface. This was done by first passing a vacuum over the surface thenpouring heptane over the outside of the graft.

After washing the graft, the graft was allowed to dry then be weighedagain, and the weight noted on the test sheet.

Once the masked graft was dried and weighed it was mounted back onto thesuspended mandrel. At this point the control samples were also mountedonto the appropriate mandrel to match the target silicone coverage asper the test matrix.

Sealant Preparation

The sealant came supplied as a 30 wt% silicone in heptane and was usedas is.

The appropriate amount of silicone was measured out to give the targetcoverage as per the test matrix and it was loaded into one of thedisposable syringe barrels. These amounts were set to account for a 25%loss when spraying.

Sealant Application

The spray head was flushed with n-Heptane to ensure correct flow. Themandrel with the graft was then mounted in the spray rig. The spray rigwas set up to spray the entire length of graft. Mounted the syringebarrel with silicone onto the spray head. The graft was rotated at 150RPM and the rate of traverse was set to 20 mm/s. The spray head wasstarted and traversed over the entire length of the graft, once itreached the opposite end the spray head was stopped and allowed toreturn to the start of the graft. The solvent was allowed to flash offbefore making another pass, after each pass a delay of 10 seconds wasobserved. This was continued till there was no dispersion left in thesyringe barrel or there was an insufficient amount to make another fullpass. Once the graft was removed from the spray rig the spray head wasagain flushed with n-heptane.

After application the graft was transferred to the rotisserie for aperiod of 6 hours then transferred to a stationary mount and allowed toair dry for a further 66 hours, the graft was confirmed dry if it didnot have a perceptible vinegar odour coming from it. Once dry, thesealed graft was weighed and the weight recorded.

Mask Removal

Once the graft has been fully dried the mask was removed. This was doneby washing the grafts in a washing machine on a ‘cotton cycle’ at 90° C.(with no detergent). This caused the PVP to be dissolved in the waterand removed and also the high temperatures aided the curing of thesilicone. When the wash was complete, the graft was hung up to air dry.Once the mask had been removed and the graft was dry, the finished graftwas weighed and the weight recorded.

Assessment of Handling

The handling of crimped grafts was assessed using tensile extensionforce testing. Mounted rimped graft samples between jaws of LloydTensile Test machine. Extend jaws by 20% (16 mm) and measure maximumforce.

Permeability Testing (ISO 7198 - Whole Graft Leak Testing)

Permeability was assessed via a whole graft porosity test (ISO 7198).Connected the graft to the pressure rig and ensure there are no leaks.Slowly increased pressure to 120 mmHg, once at that pressure theleakage, if any, from the graft surface was measured over the period of1 minute and recorded on the test sheet. Once the leak rate wasobtained, this was divided by the test surface area to obtain thepermeability reading.

Delamination Testing

Delamination was assessed via a whole graft porosity test. Connected thegraft to the pressure rig and ensured there are no leaks. Slowlyincreased pressure to 600 mmHg, once at that pressure the leakage, ifany, from the graft surface was measured over the period of 1 minute andrecorded on the test sheet. Once the leak rate was obtained, this wasdivided by the test surface area to obtain the permeability reading.

Results & Analysis

The data in the table below demonstrated the ability to get a consistentmask coverage over a range of samples and obtain the target coveragelevels of silicone.

Table 36 below lists the measured weights of the masking agent andsealant formulations after the noted processing steps. Masking agent andsealant coverages are noted in the table.

TABLE 36 Weight Summary Sample ID HH ID Initial (mg) After Masking andDrying (mg) After Sealant and Curing (mg) After Washing and Drying (mg)Mask Coverage (mg/cm²) Silicone Coverage (mg/cm²) Target SiliconeCoverage 1 220 2699 2699 3417 3412 0.00 3.64 4 2 221 2665 2665 3881 38780.00 6.23 6 3 222 2729 2729 4398 4396 0.00 8.44 8 4 223 2679 2679 45694564 0.00 9.81 10 5 224 2683 2683 4872 4868 0.00 11.27 12 6 225 26463393 4127 3374 3.90 3.81 4 7 226 2641 3382 4382 3651 3.86 5.27 6 8 2272674 3367 4910 4205 3.59 7.93 8 9 228 2692 3385 5538 4840 3.56 11.02 1010 229 2700 3314 6083 5454 3.12 14.01 12 11 230 1756 1756 2101 2093 0.002.39 4 12 231 1767 1767 2576 2574 0.00 5.73 6 13 232 1745 1745 2757 27470.00 7.12 8 14 233 1700 1700 3199 3200 0.00 10.66 10 15 234 1699 16993432 3438 0.00 12.36 12 16 235 1716 2020 2611 2294 2.16 4.11 4 17 2361735 2027 2918 2597 2.07 6.12 6 18 237 1711 1998 3215 2892 2.04 8.39 819 238 1712 2005 3487 3167 2.08 10.34 10 20 239 1728 2035 3773 3437 2.1812.14 12

Results from the table above demonstrate all woven PET graft samples hada consistent mask coverage. Crimped graft samples (samples 6-10)generally held more mass of mask compared to uncrimped graft samples(samples 17-20). This may be caused from the topography of the crimpedgraft. The above table demonstrated the ability to get a consistent maskcoverage over a range of samples and also to be able to target thecoverage levels of silicone. As the masked samples were blasted thefollowing table shows the weight data for that also.

Additionally, all woven PET graft sample achieved actual siliconecoverage levels close to the target silicone coverage levels. Crimpedgrafts tended to have slightly less actual silicone coverage compared toits target silicone coverage. On the other hand, uncrimped grafts tendedto have slightly more actual silicone coverage compared to its targetsilicone coverage. This observation may be related to the mask coverage.Less mask coverage, as seen in the uncrimped samples, allowed for highersilicone attachment to the PET graft.

As the masked graft samples were soda blasted, the following table showsthe weight before and after ablation.

Results for graft sample mass measurements before and after ablation arelisted below in Table 37.

TABLE 37 Sample ID HH ID Initial (mg) After Masking and Drying (mg)After Ablation (mg) Weight difference after ablation (mg) 6 225 26993393 3424 -31 7 226 2665 3382 3407 -25 8 227 2729 3367 3402 -35 9 2282679 3385 3416 -31 10 229 2683 3314 3351 -37 16 235 2646 2020 2054 -3417 236 2641 2027 2073 -46 18 237 2674 1998 2043 -45 19 238 2692 20052044 -39 20 239 2700 2035 2081 -46

The ablation weight data table above, shows that there was consistentweight gain for each of the 10 ablated samples. This suggested thatalthough the mask is being ablated that there is also bicarbonate beingdeposited on the surface.

Handling

The handling of the crimped grafts was assessed using the same techniqueas described above, although for this report the whole graft wasconsidered and not a section of 80 mm. The same 20% extension was used;therefore, the results are comparable. The table below shows the resultsof this testing.

The results showed that for both sets of grafts, with increasingsilicone coverages an increased in the force to extend was measured.Also evident was the increase in the force to extend between thecontrols and the grafts with an optimized mask. The controls requiredroughly double the force for the same 20% extension, strengthening thetheory that higher levels of penetration result in a higher force toextend, and furthermore worse handling.

Table 38 lists forces-to-extend values for the various samples tested.

TABLE 38 Sample ID HH Sample ID PVP Mask Conc. (%) Glycerol Cone. (% ofPVP) Silicone Coverage (mg/cm²) Force to Extend (N) Force to Extend(Normalised with Circumference) (N/mm) 1 220 0 0 3.64 0.47739 0.011 2221 0 0 6.23 0.66692 0.015 3 222 0 0 8.44 0.72483 0.016 4 223 0 0 9.810.67862 0.015 5 224 0 0 11.27 0.69653 0.016 6 225 20 5 3.81 0.178950.004 7 226 20 5 5.27 0.20019 0.005 8 227 20 5 7.93 0.21045 0.005 9 22820 5 11.02 0.34497 0.008 10 229 20 5 14.01 0.39559 0.009

The force-to-extend results show that all crimped graft samples testedincrease the amount of force to extend with increasing siliconecoverages. Additionally, the crimped graft samples with mask (samples1-5) decreased the amount of force to extend compared to the crimpedgraft samples without mask (samples 6-10). The controls (crimp graftswith no mask) require roughly double the force for the same 20%extension compared to crimp grafts with mask. This testing strengthensthe theory that higher levels of silicone penetration results in ahigher force to extend, and furthermore worse handling properties.

As depicted in FIG. 20 , the force to extend was higher for textilegrafts having the silicone applied to unmasked grafts, e.g., grafts nothaving applied masking agent (labelled as “Controls” in FIG. 20 ), ascompared to grafts having applied masking agents (labelled as “WithMask” in FIG. 20 ). This is observed even for the same levels ofsilicone coverage. While not being bound by any particular theory, it isbelieved that the application of the masking agent permits more evenapplication of the silicone by allowing the silicone to spread out thereover. In other words, the use of the masking agent facilitates thedisposition or placement of the silicone over the graft. The reducedforce is also an indication of improved handling for the grafts havingthe masking agent applied thereto. While not being bound by anyparticular theory, it is believed unmasked grafts had higher levels ofpenetration of the silicone, thereby resulting in higher forces toextend.

Permeability Testing (ISO 7198 – Whole Graft Leak Testing)

The below table shows the results of the permeability testing carriedout on all 20 samples. As expected the low coverages on the unmaskedgrafts gave high permeability reading compared to the maskedequivalents. On higher silicone coverage levels the permeability wasmore comparable.

Results for permeability testing (ISO 7198) are listed below in Table39.

TABLE 39 Sample ID HH Sample ID PVP Mask Concentration (%) GlycerolConcentration (% of PVP) Silicone Coverage (mg/cm²) Permeability(ml/min/cm²) 1 220 - - 3.64 12.82 2 221 - - 6.23 0.97 3 222 - - 8.440.48 4 223 - - 9.81 0.76 5 224 - - 11.27 0.16 6 225 20 5 3.81 2.05 7 22620 5 5.27 0.42 8 227 20 5 7.93 5.37 9 228 20 5 11.02 0.04 10 229 20 514.01 0.00 11 230 - - 2.39 22.08 12 231 - - 5.73 10.25 13 232 - - 7.120.55 14 233 - - 10.66 0.00 15 234 - - 12.36 0.00 16 235 20 5 4.11 1.3617 236 20 5 6.12 0.38 18 237 20 5 8.39 0.05 19 238 20 5 10.34 0.02 20239 20 5 12.14 0.05

Crimped graft and uncrimped grafts with no mask and low siliconecoverage (3-6 mg/cm²) demonstrated high permeability reading compared tothe masked graft equivalents. Therefore, it is observed that theapplication of masking agent lowers the amount of silicone needed toseal the graft.

Silicone coverage seals the graft with mask or without mask at about 8mg/cm². With higher silicone coverage (> 7 mg/cm²), the permeability ismore comparable for masked and non-masked graft samples.

Sample 8 (crimped graft with mask) gave an unexpected result. Thepermeability for this sample is higher than any other graft at thatconcentration. Sample 8 was expected to be one of the lowestpermeability results. This permeability result does not follow thepattern of other grafts with similar silicone coverage (6 mg/cm² and 10mg/cm²). No obvious pattern of leakage was observed. It is suggestedthere was an issue with the silicone itself or the application methodused. A hypothesis is that the silicone sat too long in air whilstspraying or there was a blockage during spraying that has caused thecoating to fail.

Delamination Testing

The table below shows the results of the delamination testing carriedout on select crimped graft samples.

Results for delamination testing detailed below in Table 40.

TABLE 40 Test Sample ID Hothouse Sample ID Mask Soda blast SiliconeCoverage mg/cmsq Leakage @ 600 mmHg 2 221 No No 6 395 ml 5 224 No No 1243 ml 7 226 20% 30 psi 6 1800 ml 133 20% 50 psi 7 95

Conclusions

All silicone coated samples with masking agent and without masking agentdid not delaminate at 600 mmHg. In other words, all samples passed thedelamination test. The silicone coated samples with masking agent andwithout masking agent may have had very minor, for example 1 to six,fine micro-jets of leakage at 600 mmHg. Nevertheless, all samples stillpassed the delamination test. Masking agent application and blasting orablating processes did not compromise the silicone attachment to thegrafts. Higher blasting pressures provided an increased amount ofnon-masked fibres on the outer surface of the graft for a strongersilicone attachment and significantly less leakage at 600 mmHg. Sodablasting at 50 psi caused minor breakage of fibres which improvedsilicone attachment (decreased leakage amount) and provided betterhandleability of the graft.

Immersion of the textile graft into the masking agent showed aconsistent method of applying PVP to crimped and uncrimped graftsamples. Spray method using force air showed an accurate way ofachieving target coverage levels of silicone. Decreasing siliconecoverage improved handling slightly. The addition of the mask improvedhandling by reducing penetration of the silicone. Crimped and uncrimpedfabric have similar permeability levels at corresponding siliconecoverages. The addition of masking agent results in lower permeabilityvalues at lower silicone coverages. At higher silicone coverages theaddition of masking agent has less effect.

In summary, the water soluble masking agent may have a viscosity fromabout 2,000 centipoise at room temperature to about 100,000 centipoiseat room temperature, including from about 50,000 centipoise at roomtemperature to about 100,000 centipoise at room temperature. The watersoluble masking agent may comprise from about 25 % w/w of thepolyvinylpyrrolidone in the glycerol to about 75 % w/w of thepolyvinylpyrrolidone in glycerol, including from about 30 % w/w of thepolyvinylpyrrolidone in the glycerol to about 70 % w/w of thepolyvinylpyrrolidone in glycerol, including from about 40 % w/w of thepolyvinylpyrrolidone in the glycerol to about 60 % w/w of thepolyvinylpyrrolidone in glycerol, more desirably including from about 45% w/w of the polyvinylpyrrolidone in the glycerol to about 55 % w/w ofthe polyvinylpyrrolidone in glycerol, in particular about 50 % w/w ofthe polyvinylpyrrolidone in the glycerol. The polyvinylpyrrolidone mayhave a molecular weight of from about 2,500 g/mol to about 55,000 g/mol,including from about 3,500 g/mol to about 50,000 g/mol, from about 5,000g/mol to about 40,000 g/mol, from about 5,000 g/mol to about 30,000g/mol, from about 5,000 g/mol to about 20,000 g/mol, and desirably fromabout 8,000 g/mol to about 10,000 g/mol.

Modifications may be made to the foregoing embodiments within the scopeof the present invention.

The following embodiments or aspects of the invention may be combined inany fashion and combination and be within the scope of the presentinvention, as follows:

Embodiment 1. A method of manufacturing a tubular graft comprising thesteps of:

-   providing a textile comprising a tubular wall disposed between a    first open end and an opposed second open end, an inner surface and    an opposed outer surface defining an interior wall portion therein    between, the tubular wall comprising a textile construction of one    or more filaments or yarns, the textile construction by itself being    permeable to liquid;-   applying a substantially water-soluble material to at least a    portion of the tubular wall; and-   applying a substantially water-insoluble sealant to at least a part    of the outer surface of the tubular wall, the substantially    water-insoluble sealant being configured to mitigate movement of    fluid through the wall of the conduit;-   wherein the water-soluble material is configured to mitigate    penetration of the sealant to the inner surface of the conduit.

Embodiment 2. The method of embodiment 1, wherein the step of applyingthe water-soluble material to at least a portion of the tubular wallcomprises applying the water-soluble material to at least a portion ofthe inner surface and a portion of the interior portion of the tubularwall.

Embodiment 3. The method of embodiment 1 or 2, wherein the step ofapplying the water-soluble material to at least a portion of the tubularwall comprises applying the water-soluble material to at least a portionof the outer surface of the tubular wall.

Embodiment 4. The method of any preceding embodiment, wherein thewater-soluble material is a solution of the water-soluble material and asolvent.

Embodiment 5. The method of any preceding embodiment, wherein thesolvent is selected form the group consisting of water, lower alcohols,and combinations thereof.

Embodiment 6. The method of any preceding embodiment, wherein thesolvent is at least partially removed prior to applying thesubstantially water-insoluble sealant.

Embodiment 7. The method of any preceding embodiment, further comprisingremoval of at least a portion of the water-soluble material is bydissolution, abrading, peeling, degrading, and combinations thereof.

Embodiment 8. The method of any preceding embodiment, wherein thewater-soluble material is selected from the group consisting ofpolyvinylpyrrolidone, glycerol, methyl cellulose, poly(ethylene glycol),poly(ethylene glycol) hydrogel, polyethylene oxide, and combinationsthereof.

Embodiment 9. The method of any preceding embodiment, wherein thesubstantially water-insoluble sealant is an elastomeric materialselected from the group consisting of moisture curing, light curing,thermo-curing, platinum catalyzed, anaerobic curing materials or acombination of these curing mechanisms.

Embodiment 10. The method of embodiment 9, wherein the elastomericmaterial is selected from the group consisting of silicones,polyurethanes, polycarbonates, thermoplastic elastomers, andcombinations thereof.

Embodiment 11. The method of any preceding embodiment, wherein one ofmore of the substantially water-soluble coating or the substantiallywater-insoluble coating further comprises a component selected from thegroup consisting of a colorant, a therapeutic agent, a dye, and afluorescent indicator.

Embodiment 12. The method of any preceding embodiment, wherein thewater-soluble material comprises polyvinylpyrrolidone having a molecularweight of between approximately 6,000 g/mol and approximately 15,000g/mol.

Embodiment 13. The method of any preceding embodiment, wherein applyingthe water-soluble material forms layer on substantially all of the innersurface of the tubular wall.

Embodiment 14. The method of any preceding embodiment, furthercomprising curing the substantially water-insoluble sealant.

Embodiment 15. The method of any preceding embodiment, furthercomprising curing the substantially water-insoluble sealant; andthereafter removing at least a portion of the water-soluble material.

Embodiment 16. The method of embodiment 14, further comprising removingsubstantially all of the water-soluble material from the inner surfaceof the tubular wall.

Embodiment 17. The method of any preceding embodiment, furthercomprising: removing at least a part of the water-soluble material fromat least a part of the outer surface of the tubular wall prior to theapplying the substantially water-insoluble sealant.

Embodiment 18. The method of any one of embodiments 15 to 17, whereinthe removing at least the portion of the water-soluble material iscarried out at a temperature of between approximately 15° C. andapproximately 140° C.

Embodiment 19. The method of any one of embodiments 15 to 18, whereinthe removing at least the portion of the water-soluble material furthercomprises the step of applying a solvent thereto.

Embodiment 20. The method of embodiment 19, wherein the solventcomprises water, lower alcohols, and combinations thereof.

Embodiment 21. The method of any one of embodiments 15 to 20, whereinthe tubular textile is agitated, rotated, spun, and shaken, or the like,during the removal of the water-soluble material.

Embodiment 22. The method of any one of embodiments 15 to 21, whereinthe removal of the water-soluble material comprises dissolving, etching,plasma etching, ablating, abrading and combinations thereof of thewater-soluble material.

Embodiment 23. The method of any preceding embodiment, wherein the stepof applying the water-soluble material further comprises spraying thewater-soluble material, brushing the water-soluble material, immersingat least a portion of the tubular wall into a solution of thewater-soluble material, and combinations thereof.

Embodiment 24. The method of any preceding embodiment, wherein thesubstantially water-insoluble sealant is a polymer solution.

Embodiment 25. The method of embodiment 24, wherein the polymer solutioncomprises an organic solvent.

Embodiment 26. The method of embodiment 25, wherein the organic solventcomprises at least one of heptane and xylene.

Embodiment 27. The method of any preceding embodiment, wherein thesubstantially water-insoluble sealant is applied by brushing, spraying,roller coating the substantially water-insoluble sealant thereon.

Embodiment 28. The method of any preceding embodiment, wherein themethod comprises one or more steps of selectively applying thesubstantially water-insoluble sealant to one or more portions of thetubular wall, such that the tubular wall comprises at least two sectionshaving substantially different amounts of the substantiallywater-insoluble sealant thereon.

Embodiment 29. The method of any one of embodiments 14 to 28, whereinthe tubular wall having the coating of the substantially water-insolublesealant is, after curing thereof, substantially impermeable to liquid.

Embodiment 30. The method of any preceding embodiment, wherein, aftercuring of the substantially water-insoluble sealant, the tubular wallhas a water permeability of about 0.16 ml/min/cm² at 120 mm Hg pressureor less than 0.16 ml/min/cm² at 120 mm Hg pressure.

Embodiment 31. A textile comprising:

-   a tubular wall disposed between a first open end and an opposed    second open end and having an inner surface and an opposed outer    surface, the tubular wall comprising a textile construction of one    or more filaments or yarns, the textile construction by itself being    permeable to liquid;-   wherein a portion of the inner surface comprises a coating of a    substantially water-soluble material thereon;-   wherein the outer surface further comprises a coating of a    substantially water-insoluble sealant disposed thereon; and-   wherein the tubular wall having the coating of the substantially    water-insoluble sealant is, after curing thereof, substantially    impermeable to liquid.

Embodiment 32. The textile of embodiment 31, wherein the water-solublematerial is selected from the group consisting of polyvinylpyrrolidone,glycerol, methyl cellulose, poly(ethylene glycol), poly(ethylene glycol)hydrogel, polyethylene oxide, and combinations thereof.

Embodiment 33. The textile of embodiment 31 or 32, wherein the coatingof the water-soluble material comprises an oleophobic layer.

Embodiment 34. The textile of any one of embodiments 31 to 33, whereinthe water-soluble material comprises polyvinylpyrrolidone having amolecular weight of between approximately 6,000 g/mol and approximately15,000 g/mol.

Embodiment 35. The textile of any one of embodiments 31 to 34, thewater-soluble material comprises polyvinylpyrrolidone and glycerol.

Embodiment 36. The textile of any one of embodiments 31 to 35, whereinthe substantially water-insoluble sealant is an elastomeric materialselected from the group consisting of moisture curing, light curing,thermo-curing, platinum catalyzed, anaerobic curing materials or acombination of these curing mechanisms.

Embodiment 37. The textile of embodiment 36, wherein the elastomericmaterial is selected from the group consisting of silicones,polyurethanes, polycarbonates, thermoplastic elastomers, andcombinations thereof.

Embodiment 38. The textile of any one of embodiments 31 to 37, whereinone of more of the substantially water-soluble coating or thesubstantially water-insoluble coating comprises a component selectedfrom the group consisting of a colorant, a therapeutic agent, a dye, anda fluorescent indicator.

Embodiment 39. The textile of any one of embodiments 31 to 38, wherein,after curing of the substantially water-insoluble sealant, the tubularwall has a water permeability of about 0.16 ml/min/cm² at 120 mm Hgpressure or less than 0.16 ml/min/cm² at 120 mm Hg pressure.

Embodiment 40. The textile of any one of embodiments 31 to 39, whereinthe textile construction is selected from the group consisting of aweave of the one or more filaments or yarns, a knit of the one or morefilaments or yarns, a braid of the one or more filaments or yarns, and aweb of the one or more filaments or yarns.

Embodiment 41. The textile of any one of embodiments 31 to 40, whereinthe tubular wall is a crimped wall having a series of peaks and valleys.

Embodiment 42. The textile of embodiment 41, wherein the substantiallywater-insoluble sealant is disposed at about 8 mg/cm² of area of thetubular wall or greater than 8 mg/cm² of area of the tubular wall.

Embodiment 43. The textile of any one of embodiments 31 to 40, whereinthe tubular wall is a non-crimped wall being substantially free of peaksand valleys.

Embodiment 44. The textile of embodiment 43, wherein the substantiallywater-insoluble sealant is disposed at about 4 mg/cm² of area of thetubular wall or greater than 4 mg/cm² of area of the tubular wall.

Embodiment 45. The textile of any one of embodiments 31 to 44, whereinthe substantially water-insoluble sealant is disposed at about 14 mg/cm²of area of the tubular wall or less than 14 mg/cm² of area of thetubular wall.

Embodiment 46. The textile of any one of embodiments 31 to 45,

-   wherein one portion of the tubular wall has a first level of the    substantially water-insoluble sealant to provide a first soft,    flexible zone;-   wherein another portion of the tubular wall has a second level of    the substantially water-insoluble sealant to provide a second zone    having a stiffness greater than the first zone; and-   wherein the second level the substantially water-insoluble sealant    is greater than the first level of the substantially water-insoluble    sealant.

Embodiment 47. The textile of any one of embodiments 31 to 46, whereinat least a portion of the coating of the substantially water-insolublesealant engages at least a portion of the one or more filaments oryarns.

Embodiment 48. The textile of any one of embodiments 31 to 47, where inthe textile is an implantable medical device.

Embodiment 49. The textile of embodiment 48, wherein the implantablemedical device is selected from the group consisting of surgicalvascular grafts, and endovascular graphs, meshes, patches, hernia plugs,vascular wraps, heart valves, filters, and the like.

Embodiment 50. The textile of any one of embodiments 31 to 49, whereinthe textile is a delivery medical device.

Embodiment 51. The textile of embodiment 50, wherein the deliverymedical device is a catheter.

Embodiment 52. A textile structure comprising:

-   a fluid permeable polymeric textile layer having opposing first and    second surfaces and a length;-   a cross-linkable water-insoluble elastomeric layer on the first    textile surface configured to render the liquid permeable polymeric    textile layer substantially impermeable to fluid when cured; and-   a substantially dried water-soluble polymer layer on the second    textile surface;-   wherein water-soluble polymer layer substantially inhibits migration    of the water-insoluble elastomeric layer onto the second surface;    and-   wherein the water-soluble polymer layer is substantially removable    by exposure to water.

Embodiment 53. The textile structure of embodiment 52, wherein theweight ratio of the cross-linkable water-insoluble elastomeric polymerto the water-soluble polymer is from about 0.1:1 to about 100:1.

Embodiment 54. The textile structure of embodiment 53, wherein theweight ratio of the cross-linkable water-insoluble elastomeric polymerto the water-soluble polymer is from about 1:1 to about 20:1.

Embodiment 55. A textile structure comprising:

-   a fluid permeable polymeric textile layer having opposing first and    second surfaces and a length;-   a crosslinked water-insoluble elastomeric polymer layer on the first    textile surface forming a substantially fluid impermeable barrier,    wherein the crosslinked water-insoluble elastomeric layer is adhered    to the first textile surface by elastomeric shrinkage; and-   a water dissolvable polymer layer dried on the second textile    surface;-   wherein the weight ratio of the crosslinked water-insoluble    elastomeric polymer to the water dissolvable polymer is from about    0.1:1 to about 100:1.

Embodiment 56. The textile construction of embodiment 55, wherein theweight ratio of the crosslinked water-insoluble elastomeric polymer tothe water dissolvable polymer is from about 1:1 to about 20:1.

Embodiment 57. A graft comprising:

-   a tubular wall disposed between a first open end and an opposed    second open end and having an inner surface and an opposed outer    surface, the tubular wall comprising a textile construction of one    or more filaments or yarns;-   wherein the outer surface comprises a coating of a substantially    water-insoluble sealant disposed thereon;-   wherein the inner surface is substantially free of the substantially    water-insoluble sealant; and-   wherein the tubular wall has a water permeability of about 0.16    ml/min/cm² at 120 mm Hg pressure or less than 0.16 ml/min/cm² at 120    mm Hg pressure.

Embodiment 58. The graft of embodiment 57, wherein the textileconstruction is selected from the group consisting of a weave of the oneor more filaments or yarns, a knit of the one or more filaments oryarns, a braid of the one or more filaments or yarns, and a web of theone or more filaments or yarns.

Embodiment 59. The graft of embodiment 57 or 58, wherein the coating isdisposed within an intermediate portion of the tubular wall between theinner surface and the opposed outer surface.

Embodiment 60. The graft of any one of embodiments 57 to 59, wherein thetubular wall is a crimped wall having a series of peaks and valleys.

Embodiment 61. The graft of any one of embodiments 57 to 60, wherein thesubstantially water-insoluble sealant is disposed at about 8 mg/cm² ofarea of the tubular wall or greater than 8 mg/cm² of area of the tubularwall.

Embodiment 62. The graft of any one of embodiments 57 to 59, wherein thetubular wall is a non-crimped wall being substantially free of peaks andvalleys.

Embodiment 63. The graft of any one of embodiments 57 to 62, wherein thesubstantially water-insoluble sealant is disposed at about 4 mg/cm² ofarea of the tubular wall or greater than 4 mg/cm² of area of the tubularwall.

Embodiment 64. The graft of any one of embodiments 57 to 63, wherein thesubstantially water-insoluble sealant is disposed at about 14 mg/cm² ofarea of the tubular wall or less than 14 mg/cm² of area of the tubularwall.

Embodiment 65. The graft of any one of embodiments 57 to 64, wherein thesubstantially water-insoluble sealant is an elastomeric materialselected from the group consisting of moisture curing, light curing,thermo-curing, platinum catalyzed, anaerobic curing materials or acombination of these curing mechanisms.

Embodiment 66. The graft of embodiment 65, wherein the elastomericmaterial is selected from the group consisting of silicones,polyurethanes, polycarbonates, thermoplastic elastomers, andcombinations thereof.

Embodiment 67. The graft of any one of embodiments 57 to 66, wherein oneof more of the substantially water-soluble coating or the substantiallywater-insoluble coating comprises a component selected from the groupconsisting of a colorant, a therapeutic agent, a dye, and a fluorescentindicator.

Embodiment 68. The graft of any one of embodiments 57 to 67, wherein thesubstantially water-insoluble sealant is selected from the groupconsisting of silicone, room temperature vulcanizing silicone,thermoplastic polyurethane, aliphatic polycarbonate, one or morethermoplastic elastomers, polycarbonate, and combinations thereof.

Embodiment 69. The graft of any one of embodiments 57 to 69,

-   wherein one portion of the tubular wall has a first level of the    substantially water-insoluble sealant to provide a first soft,    flexible zone;-   wherein another portion of the tubular wall has a second level of    the substantially water-insoluble sealant to provide a second zone    having a stiffness greater than the first zone; and-   wherein the second level the substantially water-insoluble sealant    is greater than the first level of the substantially water-insoluble    sealant.

Embodiment 70. An implantable or deliverable medical textile comprising:

-   a wall having a textile construction and having a first surface and    an opposed second surface;-   wherein the second surface comprises a coating of a substantially    water-insoluble sealant disposed thereon;-   wherein the first surface is substantially free of the substantially    water-insoluble sealant; and-   wherein the wall has a water permeability of about 0.16 ml/min/cm²    at 120 mm Hg pressure or less than 0.16 ml/min/cm² at 120 mm Hg    pressure.

Embodiment 71. An assembly for producing an implantable or deliverablemedical textile having a selectively applied water-insoluble sealantlayer, comprising:

-   a mandrel having a length, a hollow lumen disposed within a portion    of the length, at least one open end, and a plurality of    perforations through a wall of the mandrel;-   a reservoir in fluid communication with the open lumen of the    mandrel; and-   a water-soluble polymer disposed within the reservoir.

Embodiment 72. The assembly of embodiment 71, further comprising atubular graft securably disposed over a portion of the mandrel havingthe plurality of perforations.

Embodiment 73. The assembly of embodiment 71 or 72, further comprising avacuum source in fluid communication with the hollow lumen of themandrel.

Embodiment 74. The assembly of embodiment 73, further comprising amanifold configured to provide selective fluid communication between thehollow lumen of the mandrel and the reservoir and/or the vacuum source.

Embodiment 75. The assembly of any one of embodiments 71 to 74, furthercomprising a source of pressurized and/or blown air.

Embodiment 76. The assembly of embodiment 75, wherein the pressurizedand/or blown air is in fluid communication with the hollow lumen of themandrel.

Embodiment 77. The method, textile, graft, device or assembly of anypreceding embodiment, further including a support member.

Embodiment 78. The method of any one of embodiments 1 to 30, wherein thesupport member is added to the outer surface of the wall of the conduit.

Embodiment 79. The method of embodiment 78, wherein the support memberis wrapped around the outer surface of the wall of the conduit.

Embodiment 80. The method of embodiment 79, wherein the conduitcomprises a plurality of crimps, and the support member is arranged tonest between the plurality of crimps.

Embodiment 81. The method of any one of embodiments 78 to 80, wherein astep of adding the support member to the conduit is carried out prior tothe step of adding the sealant to the conduit.

Embodiment 82. The method of any one of embodiments 78 to 81, wherein astep of adding the sealant to the conduit is used, at least in part, toattach the support member to the conduit.

Embodiment 83. The method of any one of embodiments 78 to 82, whereinthe support member is a flexible, polymer member.

Embodiment 84. The method of any one of embodiments 78 to 83, whereinthe flexible support member is present on a portion of the length of thegraft.

Embodiment 85. A method of manufacturing a vascular prosthesis, themethod comprising the steps of:

-   (i) providing a conduit comprising a wall, the wall of the conduit    comprising an inner surface and an outer surface, at least a section    of the conduit being porous;-   (ii) adding a masking agent to at least a part of the porous section    of the conduit; and-   (iii) adding a sealant to at least a part of the porous section of    the conduit, the sealant being configured to mitigate movement of    fluid through the wall of the conduit;

wherein the masking agent is configured to mitigate presence of thesealant on the inner surface of the conduit.

Embodiment 86. The method of embodiment 85, wherein the sealant forms asealing layer on at least a part of the outer surface of the wall of theconduit.

Embodiment 87. The method of embodiment 85 or embodiment 86, wherein thesealant forms a sealing layer on substantially all of the outer surfaceof the wall of the conduit.

Embodiment 88. The method of any preceding embodiments 85 to 87, whereinthe masking agent forms a masking agent layer on at least a part of theinner surface of the wall of the conduit.

Embodiment 89. The method of any preceding embodiments 85 to 88, whereinthe masking agent forms a masking agent layer on substantially all ofthe inner surface of the wall of the conduit.

Embodiment 90. The method of any preceding embodiments 85 to 89, whereinsubstantially all of the conduit is porous.

Embodiment 91. The method of any preceding embodiments 85 to 90, whereinthe method comprises one or more masking agent removal steps, the, oreach, masking agent removal step comprising the step of removing atleast a part of the masking agent from the conduit.

Embodiment 92. The method of embodiment 91, wherein the method comprisesthe step of removing at least a part of the masking agent from at leasta part of the outer surface of the wall of the conduit prior to the stepof adding the sealant to the porous section of the conduit.

Embodiment 93. The method of embodiment 91 or embodiment 92, wherein themethod comprises the step of removing at least a part of the maskingagent from the inner surface of the wall of the conduit subsequent tothe step of adding the sealant to at least a part of the porous sectionof the conduit.

Embodiment 94. The method of any one of embodiments 91 to 93, whereinthe method comprises the step of removing substantially all of themasking agent from the conduit subsequent to the step of adding thesealant to at least a part of the porous section of the conduit.

Embodiment 95. The method of any one of embodiments 91 to 94, wherein atleast one of the masking agent removal steps is carried out at atemperature of between approximately 15° C. and approximately 140° C.

Embodiment 96. The method of any one of embodiments 91 to 95, wherein atleast one of the masking agent removal steps comprises the step ofremoving at least a part of the masking agent by applying a solventthereto.

Embodiment 97. The method of embodiment 96, wherein the solventcomprises water.

Embodiment 98. The method of any one of embodiments 91 to 97, whereinthe conduit is at least one of: agitated, rotated, spun, and shaken, orthe like, during at least one of the masking agent removal steps.

Embodiment 99. The method of any one of embodiments 91 to 98, wherein atleast one of the masking agent removal steps is carried out by etching,plasma etching, ablating and/or abrading the masking agent.

Embodiment 100. The method of any preceding embodiments 85 to 99,wherein the inner surface of the wall of the conduit is configured topromote the growth of biological tissue thereon.

Embodiment 101. The method of any preceding embodiments 85 to 100,wherein the masking agent comprises a polymer.

Embodiment 102. The method of embodiment 101, wherein the masking agentcomprises a water-soluble polymer.

Embodiment 103. The method of embodiment 101 or embodiment 102, whereinthe masking agent comprises at least one of: polyvinylpyrrolidone,glycerol, methyl cellulose, poly(ethylene glycol), and poly(ethyleneglycol) hydrogel.

Embodiment 104. The method of any preceding embodiments 85 to 103,wherein the masking agent is biocompatible.

Embodiment 105. The method of any preceding embodiments 85 to 104,wherein the masking agent forms a biocompatible masking agent layer whenadded to the conduit.

Embodiment 106. The method of any preceding embodiments 85 to 105,wherein the masking agent is added to at least a part of the poroussection of the conduit from a masking agent solution.

Embodiment 107. The method of embodiment 106, wherein the masking agentsolution is a polymer solution.

Embodiment 108. The method of embodiment 106 or embodiment 107, whereinthe step of adding the masking agent to at least a part of the poroussection of the conduit is performed by spraying the masking agentsolution onto at least a part of the porous section of the conduit.

Embodiment 109. The method of embodiment 108, wherein the masking agentsolution is added to the conduit by spraying the masking agent onto atleast a part of the inner surface of the wall of the conduit.

Embodiment 110. The method of any one of embodiments 106 to embodiment109, wherein the step of adding the masking agent to at least a part ofthe porous section of the conduit is performed by immersing at least apart of the porous section of the conduit in the masking agent solution.

Embodiment 111. The method of embodiment 110, wherein substantially allof the conduit is immersed in the masking agent solution.

Embodiment 112. The method of any one of embodiments 106 to 111, whereinthe masking agent solution comprises between approximately 5%weight/volume (w/v) of polymer in solution and approximately 30% w/v ofpolymer in solution.

Embodiment 113. The method of any preceding embodiments 85 to 112,wherein the step of adding the sealant to at least a part of the poroussection of the conduit does not result in the removal of the maskingagent from the porous section of the conduit.

Embodiment 114. The method of any preceding embodiments 85 to 113,wherein the masking agent is configured to biodegrade when the vascularprosthesis is implanted inside the human or animal body.

Embodiment 115. The method of any preceding embodiments 85 to 114,wherein the conduit is a woven fibrous polymer conduit.

Embodiment 116. The method of any preceding embodiments 85 to 115,wherein the sealant comprises a polymer.

Embodiment 117. The method of embodiment 116, wherein the sealant is awater-insoluble polymer.

Embodiment 118. The method of any preceding embodiments 85 to 117,wherein the sealant forms a sealing layer when added to the conduit, thesealing layer being a polymer layer.

Embodiment 119. The method of any one of embodiments 116 to 118, whereinthe sealant comprises at least one of: silicone, room temperaturevulcanising silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, and polycarbonate.

Embodiment 120. The method of any preceding embodiments 85 to 119,wherein the sealant is added to the conduit from a sealant solution.

Embodiment 121. The method of embodiment 120 wherein the sealantsolution is a polymer solution.

Embodiment 122. The method of embodiment 120 or embodiment 121, whereinthe sealant solution comprises an organic solvent.

Embodiment 123. The method of embodiment 122, wherein the sealantsolution comprises at least one of heptane and xylene.

Embodiment 124. The method of any preceding embodiments 85 to 123,wherein the sealant is added to at least a part of the porous section ofthe conduit by brushing and/or spraying the sealant thereon.

Embodiment 125. The method of any preceding embodiments 85 to 124,wherein the sealant is configured to mitigate movement of blood throughthe wall of the conduit.

Embodiment 126. The method of any preceding embodiments 85 to 125,comprising the further step of sterilising the vascular prosthesis.

Embodiment 127. The method of embodiment 126, wherein the vascularprosthesis is sterilised by way of at least one of: a gammasterilisation process, an electron beam sterilisation process, and anethylene oxide sterilisation process.

Embodiment 128. The method of any preceding embodiments 85 to 127,wherein the conduit is moveable between a contracted state and anextended state.

Embodiment 129. The method of embodiment 128, wherein the step of addingthe masking agent to at least a part of the porous section of theconduit is carried out, at least in part, while the conduit is in thecontracted state, in the extended state, and/or when moved between thecontracted state and the extended state.

Embodiment 130. The method of embodiment 128 or embodiment 129, whereinthe step of adding the sealant to at least a part of the porous sectionof the conduit is carried out, at least in part, while the conduit is inthe contracted state, in the extended state, and/or when moved betweenthe contracted state and the extended state.

Embodiment 131. The method of any preceding embodiments 85 to 130, themethod comprising one or more steps of weighing the conduit and/ormeasuring the length of the conduit, to determine, at least in part, theamount of masking agent, and/or or the amount of sealant, to add to atleast a part of the porous section of the conduit.

Embodiment 132. The method of any preceding embodiments 85 to 131,wherein the step of adding the masking agent to at least a part of theporous section of the conduit comprises the step of providing gas to theconduit.

Embodiment 133. The method of embodiment 132, wherein the gas isdirected towards the outer surface of the wall of the conduit.

Embodiment 134. The method of embodiment 132 or embodiment 133, whereinthe gas is air.

Embodiment 135. The method of any preceding embodiments 85 to 134,wherein the method comprises the step of adding a support member to theconduit.

Embodiment 136. The method of embodiment 135, wherein the support memberis added to the outer surface of the wall of the conduit.

Embodiment 137. The method of embodiment 136, wherein the support memberis wrapped around the outer surface of the wall of the conduit.

Embodiment 138. The method of embodiment 137, wherein the conduitcomprises a plurality of crimps, and the support member is arranged tonest between the plurality of crimps.

Embodiment 139. The method of any one of embodiments 135 to 138, whereinthe step of adding the support member to the conduit is carried outprior to the step of adding the sealant to the conduit.

Embodiment 140. The method of any one of embodiments 135 to 139, whereinthe step of adding the sealant to the conduit is used, at least in part,to attach the support member to the conduit.

Embodiment 141. The method of any one of embodiments 135 to 140, whereinthe support member is a flexible, polymer member.

Embodiment 142. The method of any preceding embodiments 85 to 141,wherein the method comprises one or more steps of selectively addingsealant to one or more sections of the conduit, such that the conduitcomprises at least two sections comprising substantially differentamounts of sealant thereon.

Embodiment 143. A vascular prosthesis comprising:

-   a conduit comprising a wall, the wall of the conduit comprising an    inner surface and an outer surface, at least a section of the    conduit being porous;-   wherein at least a part of the porous section comprises a sealant    configured to mitigate movement of fluid through the wall of the    conduit; and-   wherein the inner surface of the wall of the conduit is    substantially devoid of the sealant.

Embodiment 144. The vascular prosthesis of embodiment 143, wherein thesealant forms a sealing layer on at least a part of the outer surface ofthe wall of the conduit.

Embodiment 145. The vascular prosthesis of embodiment 143 or embodiment144, wherein the sealant forms a sealing layer on substantially all ofthe outer surface of the wall of the conduit.

Embodiment 146. The vascular prosthesis of any one of embodiments 143 to145, wherein substantially all of the conduit is porous.

Embodiment 147. The vascular prosthesis of any one of embodiments 143 to146, wherein the inner surface of the wall of the conduit is configuredto promote the ingrowth of biological tissue thereon.

Embodiment 148. The vascular prosthesis of any one of embodiments 143 to147, wherein the conduit is a woven fibrous polymer conduit.

Embodiment 149. The vascular prosthesis of any one of embodiments 143 to148, wherein the sealant forms a sealing layer, the sealing layer beinga polymer layer.

Embodiment 150. The vascular prosthesis of any one of embodiments 143 to149, wherein the sealant comprises at least one of: silicone, roomtemperature vulcanising silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, and polycarbonate.

Embodiment 151. The vascular prosthesis of any one of embodiments 143 to150, wherein the sealant is configured to mitigate movement of bloodthrough the wall of the conduit.

Embodiment 152. The vascular prosthesis of any one of embodiments 143 to151, wherein the vascular prosthesis is sterilised.

Embodiment 153. The vascular prosthesis of embodiment 152, wherein thevascular prosthesis is sterilised by way of at least one of thefollowing: a gamma sterilisation process, an ethylene oxidesterilisation process, and an electron beam sterilisation process.

Embodiment 154. The vascular prosthesis of any one of embodiments 143 to153, wherein the conduit is moveable between a contracted state and anextended state.

Embodiment 155. The vascular prosthesis of any one of embodiments 143 to154, wherein the conduit comprises a support member.

Embodiment 156. The vascular prosthesis of embodiment 155, wherein thesupport member is located substantially adjacent to the outer surface ofthe wall of the conduit.

Embodiment 157. The vascular prosthesis of embodiment 156, wherein thesupport member is wrapped around the outer surface of the wall of theconduit.

Embodiment 158. The vascular prosthesis of embodiment 157, wherein theconduit comprises a plurality of crimps, the support member beingarranged to nest between the plurality of crimps.

Embodiment 159. The vascular prosthesis of any one of embodiments 155 to158, wherein the sealant is arranged to, at least in part, attach thesupport member to the conduit.

Embodiment 160. The vascular prosthesis of any one of embodiments 155 to159, wherein the support member is a flexible, polymer member.

Embodiment 161. The vascular prosthesis of any one of embodiments 143 to160, wherein the conduit is configured to have at least two sectionshaving substantially different amounts of sealant thereon.

Embodiment 162. A kit of parts for manufacturing a vascular prosthesis,the kit of parts comprising:

-   (i) a conduit comprising a wall, the wall of the conduit comprising    an inner surface and an outer surface, at least a section of the    conduit being porous;-   (ii) a masking agent; and-   (iii) a sealant;

when applied to at least a part of the porous section of the conduit,the masking agent being configured to mitigate presence of the sealanton the inner surface of the conduit; and when applied to at least a partof the porous section of the conduit, the sealant being configured tomitigate movement of fluid through the wall of the conduit.

Embodiment 163. The kit of parts of embodiment 162, wherein addition ofthe sealant to at least a part of the porous section of the conduitforms a sealing layer on at least a part of the outer surface of thewall of the conduit.

Embodiment 164. The kit of parts of embodiment 162 or embodiment 163,wherein addition of the masking agent to at least a part of the poroussection of the conduit forms a masking agent layer on at least part ofthe inner surface of the wall of the conduit.

Embodiment 165. The kit of parts of any one of embodiments 162 to 164,wherein substantially all of the conduit is porous.

Embodiment 166. The kit of parts of any one of embodiments 162 to 165,the kit of parts comprising a masking agent remover, the masking agentremover being operable to remove applied masking agent from the conduit.

Embodiment 167. The kit of parts of embodiment 166, wherein the maskingagent remover comprises a solvent.

Embodiment 168. The kit of parts of embodiment 167, wherein the solventcomprises water.

Embodiment 169. The kit of parts of any one of embodiments 166 to 168,wherein the masking agent remover is operable to remove applied maskingagent from the conduit at a temperature of between approximately 15° C.and approximately 140° C.

Embodiment 170. The kit of parts of any one of embodiments 162 to 169,the kit of parts comprising an abrading tool, the abrading tool beingoperable to remove applied masking agent from the conduit.

Embodiment 171. The kit of parts of any one of embodiments 162 to 170,wherein the inner surface of the wall of the conduit is configured topromote the ingrowth of biological tissue thereon.

Embodiment 172. The kit of parts of any one of embodiments 162 to 171,wherein the masking agent comprises a polymer.

Embodiment 173. The kit of parts of embodiment 172, wherein the maskingagent comprises a water-soluble polymer.

Embodiment 174. The kit of parts of any one of embodiments 162 to 173,wherein masking agent applied to the conduit forms a masking agentlayer, the masking agent layer being a polymer layer.

Embodiment 175. The kit of parts of any one of embodiments 172 to 174,wherein the masking agent comprises at least one of:polyvinylpyrrolidone, glycerol, methyl cellulose, and poly(ethyleneglycol) hydrogel.

Embodiment 176. The kit of parts of any one of embodiments 162 to 175,wherein the masking agent is biocompatible.

Embodiment 177. The kit of parts of any one of embodiments 162 to 176,wherein masking agent applied to the conduit forms a biocompatiblemasking agent layer.

Embodiment 178. The kit of parts of any one of embodiments 162 to 177,wherein the kit of parts comprises a masking agent solution, the maskingagent solution being operable to apply masking agent to the conduit.

Embodiment 179. The kit of parts of embodiment 178, wherein the maskingagent solution is a polymer solution.

Embodiment 180. The kit of parts of embodiment 178 or embodiment 179,wherein the conduit is immersible in the masking agent solution.

Embodiment 181. The kit of parts of any one of embodiments 178 to 180,wherein the masking agent solution comprises between approximately 5%w/v of polymer in solution and approximately 30% w/v of polymer insolution.

Embodiment 182. The kit of parts of any one of embodiments 162 to 181,wherein when the masking agent and the sealant are applied to theconduit, the sealant is configured such that addition of the sealant tothe conduit does not result in the removal of the applied masking agentfrom the conduit.

Embodiment 183. The kit of parts of any one of embodiments 162 to 182,wherein the masking agent is configured to biodegrade when implantedinside the human or animal body.

Embodiment 184. The kit of parts of any one of embodiments 162 to 183,wherein the conduit is a woven fibrous polymer conduit.

Embodiment 185. The kit of parts of any one of embodiments 162 to 184,wherein the sealant comprises a polymer, optionally a water-insolublepolymer.

Embodiment 186. The kit of parts of any one of embodiments 162 to 185,wherein the sealant, when applied to the conduit, forms a sealing layer,the sealing layer being a polymer layer.

Embodiment 187. The kit of parts of embodiment 185 or embodiment 186,wherein the sealant comprises at least one of: silicone, roomtemperature vulcanising silicone, thermoplastic polyurethane, aliphaticpolycarbonate, one or more thermoplastic elastomers, and polycarbonate.

Embodiment 188. The kit of parts of any one of embodiments 162 to 187,wherein the kit of parts comprises a sealant solution operable to applysealant to the conduit.

Embodiment 189. The kit of parts of embodiment 188, wherein the sealantsolution is a polymer solution.

Embodiment 190. The kit of parts of embodiment 188 or embodiment 189,wherein the sealant solution comprises an organic solvent.

Embodiment 191. The kit of parts of embodiment 190, wherein the sealantsolution comprises at least one of heptane and xylene.

Embodiment 192. The kit of parts of any one of embodiments 162 to 191,the kit of parts comprising a sealant applicator operable to applysealant to the conduit, and/or a masking agent applicator operable toapply masking agent to the conduit.

Embodiment 193. The kit of parts of embodiment 192, wherein the sealantapplicator is an apparatus for spray coating the sealant, and/or abrush, or the like.

Embodiment 194. The kit of parts of embodiment 192 or embodiment 193,wherein the masking agent applicator is a brush, an apparatus forspray-coating the masking agent, an apparatus for dipping or immersingthe conduit in the masking agent, and/or an apparatus for wiping themasking agent onto the conduit.

Embodiment 195. The kit of parts of any one of embodiments 162 to 194,wherein the sealant, when applied to at least a part of the poroussection of the conduit, is configured to mitigate movement of bloodthrough the wall of the conduit.

Embodiment 196. The kit of parts of any one of embodiments 162 to 195,wherein the conduit is moveable between a contracted state and anextended state.

Embodiment 197. The kit of parts of any one of embodiments 162 to 196,the kit of parts comprising a further prosthesis.

Embodiment 198. The kit of parts of embodiment 197, wherein the furtherprosthesis is at least one of: a biological heart valve, a syntheticheart valve, a cardiac assist device, and a ventricular assist device,or the like.

Embodiment 199. The kit of parts of any one of embodiments 162 to 198,the kit of parts comprising a weighing device and/or a device formeasuring the length of the conduit.

Embodiment 200. The kit of parts of any one of embodiments 162 to 199,the kit of parts comprising a gas flow apparatus operable to provide gasflow to the conduit.

Embodiment 201. The kit of parts of embodiment 200, wherein the gas isair.

Embodiment 202. A vascular system, the vascular system comprising:

-   a vascular prosthesis manufactured according to any one of    embodiments 85 to 142; and-   a further prosthesis;-   wherein the vascular prosthesis is connected to the further    prosthesis, such that fluid can flow between the vascular prosthesis    and the further prosthesis.

Embodiment 203. The vascular system of embodiment 202, wherein thefurther prosthesis is at least one of: a biological heart valve, asynthetic heart valve, a cardiac assist device, and a ventricular assistdevice, or the like.

Embodiment 204. A method of implanting a vascular prosthesis, the methodcomprising the steps of:

-   providing a vascular prosthesis manufactured using the method of any    one of embodiments 85 to 142;-   connecting an inlet of the vascular prosthesis to a first blood    vessel; and-   connecting an outlet of the vascular prosthesis to a second blood    vessel;-   such that blood can flow between the first and second blood vessels    through the vascular prosthesis.

Embodiment 205. The method of embodiment 204, wherein the first andsecond blood vessels are formed from a blood vessel which is diseased,or has been severed, bisected, or the like.

Embodiment 206. A method of implanting a vascular prosthesis, the methodcomprising the steps of:

-   providing a vascular prosthesis according to any one of embodiments    143 to 161;-   connecting the vascular prosthesis to a first blood vessel; and-   connecting the vascular prosthesis to a second blood vessel;-   such that blood can flow between the first and second blood vessels    through the vascular prosthesis.

Embodiment 207. The method of embodiment 206, wherein the first andsecond blood vessels are formed from a blood vessel which is diseased,or has been severed, bisected, or the like.

Embodiment 207. A method of implanting a vascular system, the methodcomprising the steps of:

-   providing a vascular system, the vascular system comprising:-   a vascular prosthesis manufactured according to any one of    embodiments 85 to 142; and-   a further prosthesis;-   wherein the vascular prosthesis is connectable to the further    prosthesis;-   connecting the vascular prosthesis to the further prosthesis, such    that blood can flow therebetween;-   connecting an end of a blood vessel to the vascular prosthesis; and-   connecting the further prosthesis to the heart;-   such that blood can flow between the blood vessel and the heart    through the vascular system.

Embodiment 209. The method of embodiment 208, wherein the furtherprosthesis is at least one of: a biological heart valve, a syntheticheart valve, a cardiac assist device, and a ventricular assist device,or the like.

Embodiment 210. A method for manufacturing a substantially impermeabletextile graft comprising:

-   providing a textile graft having a first surface and an opposed    second surface;-   providing a water soluble masking agent comprising    polyvinylpyrrolidone and glycerol without mixing or combining the    polyvinylpyrrolidone and the glycerol with added water;-   applying the water soluble masking agent to a portion of the first    surface of the textile graft;-   providing a water insoluble sealing agent;-   maintaining the second surface of the textile graft receptive for    receiving the water insoluble sealing agent; and-   applying the water insoluble sealing agent to the second surface of    the textile graft.

Embodiment 211. The method of embodiment 210, wherein the water solublemasking agent consists essentially of polyvinylpyrrolidone and glycerol.

Embodiment 212. The method of any previous embodiments starting with210, wherein the water soluble masking agent comprises from about 25 %w/w of the polyvinylpyrrolidone in the glycerol to about 75 % w/w of thepolyvinylpyrrolidone in glycerol.

Embodiment 213. The method of any previous embodiments starting with210, wherein the water soluble masking agent is flowable.

Embodiment 214. The method of any previous embodiments starting with210, wherein the water soluble masking agent is prepared by dissolvingthe polyvinylpyrrolidone in the glycerol.

Embodiment 215. The method of any previous embodiments starting with210, wherein the polyvinylpyrrolidone is dissolved into the glycerolwith one or more of stirring and application of heat.

Embodiment 216. The method of any previous embodiments starting with210, wherein the step of maintaining the second surface of the textilegraft receptive for receiving the water insoluble sealing agentcomprises preventing egress of the water soluble masking agent from thefirst surface to the second surface.

Embodiment 217. The method of any previous embodiments starting with210, wherein the step of preventing the egress of the water solublemasking agent from the first surface to the second surface comprisessubstantially prohibiting wicking of the water soluble masking agentfrom the first surface to the second surface.

Embodiment 218. The method of any previous embodiments starting with210, wherein the step of maintaining the second surface of the textilegraft receptive for receiving the water insoluble sealing agentcomprises removal of the water soluble masking agent from the secondsurface.

Embodiment 219. The method of any previous embodiments starting with210, wherein the step of removal of the water soluble masking agent fromthe second surface comprises dissolving the water soluble masking agentfrom the second surface.

Embodiment 220. The method of any previous embodiments starting with210, wherein the step of removal of the water soluble masking agent fromthe second surface comprises ablating the water soluble masking agentfrom the second surface.

Embodiment 221. The method of any previous embodiments starting with210, wherein the polyvinylpyrrolidone has a molecular weight of fromabout 2,500 g/mol to about 55,000 g/mol.

Embodiment 222. The method of any previous embodiments starting with210, wherein the water insoluble sealing agent comprises a materialselected from the group consisting of silicones, polyurethanes,polycarbonates, thermoplastic elastomers, and combinations thereof.

Embodiment 223 The method of any previous embodiments starting with 210,wherein the step of applying the water insoluble sealing agent to thesecond surface of the textile graft comprises spraying water insolublesealing agent onto the second surface of the textile graft.

Embodiment 224. The method of any previous embodiments starting with210, wherein the spraying is forced air spraying or ultrasonic spraying.

Embodiment 225. The method of any previous embodiments starting with210, further comprising removing the water soluble masking agent afterthe step of applying the water insoluble sealing agent.

Embodiment 226. The method of any previous embodiments starting with210, further comprising curing the water insoluble sealing agent.

Embodiment 227 The method of any previous embodiments starting with 210,wherein, after curing of the water insoluble sealing agent, the textilegraft is substantially impermeable to liquid.

Embodiment 228. The method of any previous embodiments starting with210, wherein, after curing of the water insoluble sealing agent, thetextile graft has a water permeability of about 0.16 ml/min/cm² at 120mm Hg pressure or less than 0.16 ml/min/cm² at 120 mm Hg pressure.

Embodiment 229. The method of any previous embodiments starting with210, wherein the textile graft is a tubular textile graft.

Embodiment 230. The method of any previous embodiments starting with210, wherein the water soluble masking agent has a viscosity from about2,000 centipoise at room temperature to about 100,000 centipoise at roomtemperature.

Embodiment 231. The method of any previous embodiments starting with210, wherein the water soluble masking agent has a viscosity from about50,000 centipoise at room temperature to about 100,000 centipoise atroom temperature.

Embodiment 232. A method for manufacturing a substantially impermeabletextile graft comprising:

-   providing a textile graft having a first surface and an opposed    second surface;-   providing a water soluble masking agent selected from the group    consisting of polyvinylpyrrolidone, glycerol, methyl cellulose,    poly(ethylene glycol), poly(ethylene glycol) hydrogel, polyethylene    oxide, and combinations thereof;-   applying the water soluble masking agent to a portion of the first    surface of the textile graft, wherein a portion of the water    insoluble sealing agent is optionally disposed on the second surface    of the textile graft;-   ablating a portion of the water soluble masking agent from the    second surface of the textile graft;-   providing a water insoluble sealing agent selected from the group    consisting of silicones, polyurethanes, polycarbonates,    thermoplastic elastomers, and combinations thereof; and-   applying the water insoluble sealing agent to the second surface of    the textile graft.

Embodiment 233. The method of embodiment 232, wherein the step ofablating further comprises providing a flow of solid particulatesagainst the second surface of the textile graft.

Embodiment 234. The method of any previous embodiments starting with232, wherein the solid particulates are a material selected from thegroup consisting of sodium bicarbonate, sodium chloride, sugar,magnesium sulphate, potassium chloride, and combinations thereof.

Embodiment 235. The method of any previous embodiments starting with232, wherein the solid particulates have an average particle size acrosstheir largest dimension from about 50 microns to about 300 microns.

Embodiment 236. The method of any previous embodiments starting with232, wherein the solid particulates have a Moh’s hardness from about 1to about 4.

Embodiment 237. The method of any previous embodiments starting with232, wherein the solid particulates are sprayed at a pressure from about10 psig to about 50 psig.

Embodiment 238. The method of any previous embodiments starting with232, further comprising curing the water insoluble sealing agent.

Embodiment 239. The method of any previous embodiments starting with232, wherein, after curing of the water insoluble sealing agent, thetextile graft is substantially impermeable to liquid.

Embodiment 240. The method of any previous embodiments starting with232, wherein, after curing of the water insoluble sealing agent, thetextile graft has a water permeability of about 0.16 ml/min/cm² at 120mm Hg pressure or less than 0.16 ml/min/cm² at 120 mm Hg pressure.

Embodiment 241. The method of any previous embodiments starting with232, further comprising removing the water soluble masking agent afterthe step of applying the water insoluble sealing agent.

Embodiment 240. The method of any previous embodiments starting with232, further comprising adding a dye to the water insoluble sealingagent.

Embodiment 241. The method of any previous embodiments starting with232, further comprising adding a dye to the water soluble masking agent.

Embodiment 242. A textile graft made by the method of any of theembodiments 210-231.

Embodiment 243. A textile graft made by the method of any of theembodiments 232-241.

Embodiment 244. A method of providing a sealant to a textile graftcomprising:

-   providing a textile graft having a first surface and an opposed    second surface and having a textile pattern of yarns inter-engaging    yarns and interstices between or in the yarns;-   providing a water soluble masking agent selected from the group    consisting of polyvinylpyrrolidone, glycerol, methyl cellulose,    poly(ethylene glycol), poly(ethylene glycol) hydrogel, polyethylene    oxide, and combinations thereof;-   applying the water soluble masking agent to at least a portion of    the first surface of the textile graft, wherein a portion of the    water soluble masking agent is further disposed at a plurality of    the interstices;-   providing a water insoluble sealing agent selected from the group    consisting of silicones, polyurethanes, polycarbonates,    thermoplastic elastomers, and combinations thereof; and-   applying the water insoluble sealing agent to the second surface of    the textile graft and over the portion of the water soluble masking    agent being disposed at a plurality of the interstices;-   whereby the water insoluble sealing agent spreads over the water    soluble masking agent to provide one or more of the following: a    substantially homogenous layer of the water insoluble sealing agent;    a substantially uniform and uninterrupted coating of the water    insoluble sealing agent; a layer of water insoluble sealing agent    having a substantially uniform weight per given area of application;    a substantially liquid impermeable barrier to the underlying textile    graft surface; a substantially lower force to extend a graft coated    with the water insoluble sealing agent as compared to comparable    grafts which have not used a masking agent; a substantially less    amount of water insoluble sealing agent to provide a substantially    liquid impermeable barrier to the underlying textile graft surface    as compared to comparable grafts which have not used a masking    agent; and combinations thereof.

Embodiment 245. The method of embodiment 244, further comprisingremoving the water soluble masking agent after the step of applying thewater insoluble sealing agent.

Embodiment 246. The method of any previous embodiments starting with244, further comprising curing the water insoluble sealing agent.

Embodiment 247. The method of any previous embodiments starting with244, wherein, after curing of the water insoluble sealing agent, thewater insoluble sealing agent is disposed over the interstices betweenand in the yarns.

Embodiment 248. The method of any previous embodiments starting with244, wherein, the textile graft is substantially impermeable to liquid.

Embodiment 249. The method of any previous embodiments starting with244, wherein, after curing of the water insoluble sealing agent, thetextile graft has a water permeability of about 0.16 ml/min/cm² at 120mm Hg pressure or less than 0.16 ml/min/cm² at 120 mm Hg pressure.

Embodiment 250. A textile graft made by the method of any of theembodiments 244-249.

Embodiment 251. A method of sealing a textile graft comprising:

-   applying a coating of a substantially water soluble masking agent,    having a viscosity of from about 2,000 centipoise at room    temperature to about 100,000 centipoise at room temperature, to at    least a portion of a luminal surface of the textile graft, wherein a    portion of the water soluble masking agent is further disposed at a    plurality of interstices in the graft; and-   applying a water insoluble sealing agent to an outer graft surface    opposing the luminal surface of the graft;-   wherein the water soluble masking agent causes one or more of the    following to occur:-   a substantially homogenous layer of the water insoluble sealing    agent is formed; a substantially uniform and uninterrupted coating    of the water insoluble sealing agent is formed; a layer of water    insoluble sealing agent having a substantially uniform weight per    given area of application; a substantially liquid impermeable    barrier to the underlying textile graft surface; a substantially    lower force to extend a graft coated with the water insoluble    sealing agent as compared to comparable grafts which have not used a    masking agent; a substantially less amount of water insoluble    sealing agent to provide a substantially liquid impermeable barrier    to the underlying textile graft surface as compared to comparable    grafts which have not used a masking agent; and combinations    thereof.

Embodiment 252. The method of any of the embodiments claim 210 to 231,wherein the steps of applying the water soluble masking agent andapplying the water insoluble sealing agent are performed substantiallyconcurrently.

Embodiment 253. The method of embodiment 252, wherein the step ofapplying the water soluble masking agent further comprises applyingheat, directly or indirectly, to the water soluble masking agent.

Embodiment 254. The method of embodiment 253, wherein the step ofapplying water insoluble sealing agent further comprises applyingcooling, directly or indirectly, to the second surface of the textilegraft.

Embodiment 255. The method of any of the embodiments claim 210 to 231,further comprising:

-   controlling temperature of the water soluble masking agent while    apply the water soluble masking agent to the first surface of the    textile graft to control flow of the water soluble masking agent at    the first surface of the textile graft; and-   controlling temperature at or near the second surface of the textile    graft while apply the water soluble masking agent to the first    surface of the textile graft to control the flow of the water    soluble masking agent towards the second surface of the textile    graft.

Embodiment 256. The method of claim 255, wherein the step of controllingthe temperature at or near the second textile surface is performed priorto the step of applying the water insoluble sealing agent to the secondsurface of the textile graft.

Embodiment 257. The method of claim 255, wherein the step of controllingthe temperature at or near the second textile surface is performedduring the step of applying the water insoluble sealing agent to thesecond surface of the textile graft.

Embodiment 258. The method of claim 255, wherein the step of controllingthe temperature at or near the second textile surface is performed priorthe step of applying the water insoluble sealing agent to the secondsurface of the textile graft and during the step of applying the waterinsoluble sealing agent to the second surface of the textile graft.

What is claimed is:
 1. An implantable textile graft comprising: aconduit, comprising a liquid permeable textile tubular wall comprisingan inner surface, an intermediate portion, and an outer surface, saidtextile tubular wall comprising one or more yarns; said conduitcomprises a cured layer comprising a substantially water-insoluble,non-biodegradable elastomeric sealant selected from the group consistingof a silicone-containing polymer, a polyurethane-containing polymer, apolycarbonate-containing polymer, and combinations thereof, disposed onsaid outer surface and said intermediate portion; wherein (i) said curedlayer on said outer surface does not exhibit signs of delamination(bubbles) when said conduit is pressurized with water at 120 mmHg; and(ii) said conduit is substantially water impermeable when said conduitis pressurized at 120 mmHg.
 2. The graft of claim 1, wherein said curedlayer on said outer surface does not exhibit signs of delamination(bubbles) when said conduit is pressurized with water for 1 minute atabout 600 mmHg.
 3. The graft of claim 1, wherein said cured layer onsaid outer surface does not exhibit signs of delamination (bubbles) whensaid conduit is pressurized with water for 1 minute in a pressure rangeof from 120 mmHg to 600 mmHg.
 4. The graft of claim 1, wherein, aftercuring of the substantially water-insoluble elastomeric sealant, thetextile tubular wall is configured to obviate the leaking of bloodtherefrom at a blood pressure of up to about 200 mmHg.
 5. The graft ofclaim 1, wherein, after curing of the substantially water-insolubleelastomeric sealant, the textile tubular wall is configured to obviatethe leaking of blood therefrom at a blood pressure of up to about 300mmHg.
 6. The graft of claim 1, wherein, after curing of thesubstantially water-insoluble elastomeric sealant, the textile tubularwall has a water permeability of about 0.16 ml/min/cm² at 120 mmHgpressure or less than 0.16 ml/min/cm² at 120 mmHg pressure.
 7. The graftof claim 1, wherein the textile construction is selected from the groupconsisting of a weave of the one or more multi-filament yams, a knit ofthe one or more multifilament yarns, a braid of the one or moremulti-filament yarns, a web of the one or more multi-filament yarns, anda felt of the one or more multi-filament yarns.
 8. The graft of claim 1,wherein the textile tubular wall is a crimped wall having a plurality ofpeaks and valleys; and wherein the substantially water-insoluble sealantis disposed at about 8 mg/cm² of area of the textile tubular wall orgreater than 8 mg/cm² of area of the textile tubular wall.
 9. The graftof claim 1, wherein the textile tubular wall is a non-crimped wall beingsubstantially free of peaks and valleys; and wherein the substantiallywater-insoluble elastomeric sealant is disposed at about 4 mg/cm² ofarea of the textile tubular wall or greater than 4 mg/cm² of area of thetextile tubular wall.
 10. The graft of claim 1, wherein thesubstantially water-insoluble elastomeric sealant is disposed betweenabout 4 mg/cm² and 19 mg/cm² of area of the textile tubular wall. 11.The graft of claim 1, wherein the inner surface is at least 70% free ofthe substantially water-insoluble elastomeric sealant.
 12. The graft ofclaim 1, wherein the inner surface is at least 95% free of thesubstantially water-insoluble elastomeric sealant.
 13. The graft ofclaim 1, wherein one portion of the tubular wall has a first level ofthe substantially water-insoluble elastomeric sealant to provide a firstsoft, flexible zone; wherein another portion of the tubular wall has asecond level of the substantially water insoluble elastomeric sealant toprovide a second zone having a stiffness greater than the first zone;and wherein the second level of the substantially water-insolubleelastomeric sealant is greater than the first level of the substantiallywater-insoluble sealant.
 14. The graft of claim 1, wherein the tubularwall has a plurality of portions having different levels of thesubstantially water-insoluble elastomeric sealants to provide aplurality of portions having different levels of stiffnesses.
 15. Thegraft of claim 1, wherein the water-insoluble elastomeric sealant ispenetrating no more than about 50% into a fabric thickness of thetubular wall.
 16. The graft of claim 1, wherein the water-insolubleelastomeric sealant is penetrating up to at least about 50% into afabric thickness of the tubular wall.
 17. The graft of claim 1, whereininner surface is configured to promote biological tissue growth thereon.18. An implantable textile graft comprising: a conduit, comprising aliquid permeable textile tubular wall comprising an inner surface, anintermediate portion, and an outer surface, said textile tubular wallcomprising one or more yarns; said conduit comprises a cured layercomprising a substantially water-insoluble, non-biodegradableelastomeric sealant selected from the group consisting of asilicone-containing polymer, a polyurethane-containing polymer, apolycarbonate-containing polymer, and combinations thereof, disposed onsaid outer surface and said intermediate portion; wherein (i) thewater-insoluble elastomeric sealant is penetrating at about 50% or lessthan 50% into a fabric thickness of the tubular wall; and (ii) saidconduit is substantially water impermeable when said conduit ispressurized at about 120 mm Hg.